Dot-matrix flexible thermoelectric energy collection structure and preparation method thereof

Abstract

The invention discloses a dot-matrix flexible thermoelectric energy collection structure and a preparation method thereof, and the collection structure comprises two layers of flexible glass fiber substrates; the thermoelectric units are arranged between the two layers of flexible glass fiber substrates, the multiple thermoelectric units are arranged in the full-length direction of the flexible glass fiber substrates, and a zigzag thermopile is formed among the multiple thermoelectric units; silver electrode films are arranged at the tops and the bottoms of the thermoelectric units and are used for electrical connection of the thermoelectric units; wherein the flexible glass fiber substrate located on the bottom layer is used for being attached to the surface of a heat source, and the flexible glass fiber substrate located on the top layer makes contact with a cold end area of the heat source. Based on a high-performance thermoelectric material, a flexible thermoelectric thick film structure is finally formed through the screen printing technology, the output power density is high, the mechanical performance is high, the flexible thermoelectric thick film structure can adapt to heat energy collection work of a complex curved surface, installation is easy, and the flexible thermoelectric thick film structure has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible thermoelectric energy collection devices, and in particular relates to a lattice-type flexible thermoelectric energy collection structure and a preparation method thereof. Background Art

[0002] With the rapid development of science and technology, the amount of energy required for scientific research and social development is becoming increasingly huge. Traditional forms of energy, such as coal, oil, and natural gas, are being used in large quantities. The rapid reduction of these non-renewable energy sources has led to many worrying problems. Therefore, it is very important to find a practical solution to the problem of energy shortage. Energy harvesting technology is a solution that collects energy that is widely present in the environment to store energy and power equipment. It mainly relies on the collection of available energy such as solar energy, thermal energy, and mechanical energy. Thermal energy is widely present in buildings, equipment, and even on the surface of the human body. Therefore, thermoelectric energy harvesting has a high application value in the fields of industry, manufacturing, and medical electronics.

[0003] At present, the widely used traditional rigid thermoelectric devices are large in size and mass, and cannot collect energy from irregular surfaces. Although flexible thermoelectric devices are lightweight, they have problems such as high cost, weak output capacity, and poor mechanical reliability. Therefore, based on high-performance thermoelectric materials, a high-power density and highly reliable flexible thermoelectric energy collector is developed through thin film preparation technology to make up for the shortcomings of existing flexible thermoelectric energy devices. At the same time, it can provide a solution for waste heat recovery from irregular surfaces such as equipment and human bodies, and achieve the purpose of improving environmental energy utilization. Summary of the invention

[0004] The purpose of the present invention is to provide a lattice-type flexible thermoelectric energy collection structure and a preparation method thereof, so as to solve the technical defects in the prior art that, although flexible thermoelectric devices are light, they have the problems of high cost, weak output capacity, poor mechanical reliability, etc.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a lattice-type flexible thermoelectric energy collection structure is provided, comprising: Flexible fiberglass base with two layers; A thermoelectric unit is disposed between two layers of the flexible glass fiber substrate, and a plurality of thermoelectric units are arranged along the length of the flexible glass fiber substrate, and a zigzag thermopile is formed between the plurality of thermoelectric units; The top and bottom of the thermoelectric unit are both provided with a silver electrode film, and the silver electrode film is used for electrical connection of the thermoelectric unit; The flexible glass fiber substrate located at the bottom layer is used to adhere to the surface of the heat source, and the flexible glass fiber substrate located at the top layer is in contact with the cold end area of ​​the heat source.

[0006] Furthermore, the multiple thermoelectric units are connected in series; Each thermoelectric unit includes an N-type thermoelectric arm and a P-type thermoelectric arm, and the tops of the N-type thermoelectric arm and the P-type thermoelectric arm are connected by a silver electrode film; The bottoms of the N-type thermoelectric arm and the P-type thermoelectric arm are connected to the N-type thermoelectric arm and the P-type thermoelectric arm in another adjacent thermoelectric unit through a silver electrode film.

[0007] Furthermore, the N-type thermoelectric arm and the P-type thermoelectric arm are both circular thick films, and are electrically connected to the silver electrode film through high-temperature conductive silver paste.

[0008] Furthermore, the angle between the silver electrode film on the top of the N-type thermoelectric arm and the silver electrode film on the bottom of the N-type thermoelectric arm is an acute angle.

[0009] Furthermore, conductive silver paste is used to bond metal leads at both ends of the thermopile so that the thermopile can collect thermoelectric output.

[0010] In a second aspect, a method for preparing a lattice-type flexible thermoelectric energy collection structure is provided, wherein the structure is prepared by the method, comprising: Clean, dry and cut the flexible fiberglass substrate; On the cut flexible glass fiber substrate, preparing two patterns of silver electrode films, and performing drying and high-temperature annealing treatment on the two patterns of silver electrode films; Cutting the flexible glass fiber substrate along the silver electrode film after high temperature annealing to obtain flexible glass fiber substrates with two patterns; The rigid alumina substrate is cleaned and dried; Prepare two kinds of thermoelectric material slurries, respectively print a bismuth telluride thick film and an antimony telluride thick film on the rigid alumina substrate after drying, and dry and anneal the bismuth telluride thick film and the antimony telluride thick film; Both sides of the annealed bismuth telluride thick film and antimony telluride thick film are polished and respectively bonded to flexible glass fiber substrates with two patterns through high temperature resistant conductive silver paste.

[0011] Further, two patterns of silver electrode films are prepared, specifically including: The screen printing method was used, and 3-5 g of 2-3 μm silver powder, 0.6-1 g of epoxy resin, 0.2-0.5 g of polyetheramine, and 0.4-0.6 g of pineneol were selected; Among them, epoxy resin is used as a binder and pinene alcohol is used as a solvent to adjust the viscosity of the slurry. After the slurry is evenly stirred, a screen with a mesh size of 200 is used to print the silver electrode film arrays with upper and lower patterns through a screen printing process.

[0012] Furthermore, the thickness of the silver electrode thin film arrays of the upper and lower patterns is 20-40 μm.

[0013] Furthermore, the preparation of two thermoelectric material slurries specifically includes: When preparing the screen printing paste prepared by bismuth telluride powder, 3-5g of 500-mesh telluride powder, 2.2-4g of 500-mesh bismuth powder, 0.1-0.3g of ethyl cellulose and 0.55-0.8g of diethylene glycol butyl ether acetate are selected; When preparing the screen printing paste prepared by antimony telluride powder, 3-5g of 500-mesh tellurium powder, 0.8-1.5g of 500-mesh bismuth powder, 1.5-2g of 500-mesh antimony powder, 0.1-0.2g of ethyl cellulose and 0.5-1.1g of diethylene glycol butyl ether acetate are selected; Wherein, the ethyl cellulose as a binder and the diethylene glycol butyl ether acetate as a solvent are used to adjust the viscosity of the slurry; After the slurry is stirred evenly, a circular thick film array of thermoelectric units is printed using a stainless steel plate with a customized pattern.

[0014] Furthermore, the thickness of the circular thick film array is 350-400 μm.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 3. High-temperature conductive silver paste has excellent conductive properties, which can ensure efficient and stable electrical connection between the N-type thermoelectric arm and the P-type thermoelectric arm and the silver electrode film, helping to reduce resistance loss and improve energy collection efficiency.

[0016] 4. The sharp angle design helps to make the heat transfer path inside the thermoelectric arm smoother, reducing heat loss and accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is the overall structural diagram of the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 2 It is a schematic diagram of the structure of a single pair of thermoelectric arms in the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 3 Figure 4 and are schematic diagrams of two silver electrode patterns in the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 5 It is a schematic diagram of a thermopile in a lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 6 This is a schematic diagram of the application of the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 7 This is a test diagram of the output performance of the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Figure 8 It is a flow chart of the method for preparing the lattice-type flexible thermoelectric energy collection structure provided by the present invention; Among them: 1. N-type thermoelectric arm; 2. P-type thermoelectric arm; 3. Silver electrode film; 4. Flexible glass fiber substrate; 5. Heat source. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0022] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0023] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] With the rapid development of science and technology, the amount of energy required for scientific research and social development is becoming increasingly huge. Traditional forms of energy, such as coal, oil, and natural gas, are being used in large quantities. The rapid reduction of these non-renewable energy sources has led to many worrying problems. Therefore, it is very important to find a practical solution to the problem of energy shortage. Energy harvesting technology is a solution that collects energy that is widely present in the environment to store energy and power equipment. It mainly relies on the collection of available energy such as solar energy, thermal energy, and mechanical energy. Thermal energy is widely present in buildings, equipment, and even on the surface of the human body. Therefore, thermoelectric energy harvesting has a high application value in the fields of industry, manufacturing, and medical electronics.

[0025] At present, the widely used traditional rigid thermoelectric devices are large in size and mass, and cannot collect energy from irregular surfaces. Although flexible thermoelectric devices are lightweight, they have problems such as high cost, weak output capacity, and poor mechanical reliability. Therefore, based on high-performance thermoelectric materials, a high-power density and highly reliable flexible thermoelectric energy collector is developed through thin film preparation technology to make up for the shortcomings of existing flexible thermoelectric energy devices. At the same time, it can provide a solution for waste heat recovery from irregular surfaces such as equipment and human bodies, and achieve the purpose of improving environmental energy utilization.

[0026] In order to solve the above technical defects, the inventor provides a lattice-type flexible thermoelectric energy collection structure and a preparation method thereof.

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings: like Figure 1-Figure 7As shown, in an embodiment of the present invention, a first aspect provides a dot matrix flexible thermoelectric energy collection structure, including a flexible glass fiber substrate 4, which is provided with two layers; a thermoelectric unit is arranged between the two layers of flexible glass fiber substrate 4, and a plurality of thermoelectric units are arranged along the length direction of the flexible glass fiber substrate 4, and a zigzag thermoelectric pile is formed between the plurality of thermoelectric units. According to the thermoelectric effect, when there is a temperature difference between the top and the bottom of each pair of thermoelectric arms, a thermoelectric potential will be formed at both ends of the thermoelectric arm; when there is the same temperature difference in each pair of thermoelectric arms in the thermoelectric pile, the thermoelectric potential generated by each is the same, and the total output of the thermoelectric pile is equal to the output of a single pair of thermoelectric arms multiplied by the total number of pairs of thermoelectric arms; a silver electrode film 3 is provided on the top and bottom of the thermoelectric unit, and the silver electrode film 3 is used for the electrical connection of the thermoelectric unit; wherein, the flexible glass fiber substrate 4 located at the bottom layer is used to adhere to the surface of the heat source 5, and the flexible glass fiber substrate 4 located at the top layer is in contact with the cold end area of ​​the heat source 5. By adopting the zigzag thermopile design, the temperature gradient on the surface of the heat source 5 can be more effectively utilized. The zigzag layout not only increases the contact area between the thermoelectric unit and the heat source 5, but also optimizes the heat transfer path in the thermoelectric material, thereby improving the thermoelectric conversion efficiency, so that the structure can more efficiently collect and convert the heat energy generated by the heat source 5, and provide continuous power support for the equipment. The use of a flexible glass fiber substrate 4 as the supporting structure of the thermoelectric unit makes the entire energy collection structure have excellent flexibility and bendability, and can adapt to various complex shapes of the heat source 5 surface, such as human skin, irregular surfaces of machinery and equipment, etc., thereby broadening its application range; and the flexible glass fiber substrate 4 has good high temperature resistance, wear resistance and corrosion resistance, and can protect the thermoelectric unit from damage by the external environment; at the same time, the use of the silver electrode film 3 not only ensures the stability and reliability of the electrical connection, but also improves the conductivity of the entire structure, further enhancing its durability. In summary, due to its light structure and good flexibility, this lattice-type flexible thermoelectric energy collection structure is easier and faster to install, without the need for complex fixtures or tools. When it is necessary to maintain or replace some thermoelectric units, it can be operated more easily, reducing maintenance costs and time. Furthermore, a series connection is adopted between multiple thermoelectric units to achieve the technical effects of electrical series connection and thermal parallel connection, thereby significantly improving the total voltage output of the entire energy collection structure; wherein each thermoelectric unit includes an N-type thermoelectric arm 1 and a P-type thermoelectric arm 2, and the tops of the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 are connected by a silver electrode film 3; the bottoms of the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 are connected to the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 in another adjacent thermoelectric unit through a silver electrode film 3.The combination of the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 constitutes the basic unit of the thermocouple, which is sensitive to temperature gradient and can convert thermal energy into electrical energy. By accurately connecting these thermoelectric arms in series, the temperature difference generated by the heat source 5 can be more effectively utilized, the thermoelectric conversion process can be optimized, and the energy conversion efficiency can be improved; at the same time, the thermoelectric units connected in series are closely connected through the silver electrode film 3, which not only ensures the stability and reliability of the electrical connection, but also enhances the mechanical strength of the entire structure. The silver electrode film 3, as a good conductor and adhesive, can effectively fix the thermoelectric arms together to prevent the structure from loosening or damage due to vibration or external force. It is worth noting that the main component of the flexible glass fiber substrate 4 is silicon dioxide, which has good high temperature resistance and flexibility. The flexible glass fiber substrate 4 is bonded to the heat source 5 and the cold end surface to form a certain temperature gradient, and energy collection is achieved through thermoelectric conversion. The main component of the electrical connection unit is silver, which has good stability and conductivity. It is attached to the flexible glass fiber substrate 4 and is bonded to both ends of the thermocouple to achieve the purpose of electrical connection and reduce contact resistance.

[0028] like Figure 2As shown, both the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 are circular thick films, and are electrically connected to the silver electrode film 3 through high-temperature conductive silver paste. The silver electrode film 3 on the top of the N-type thermoelectric arm 1, the high-temperature conductive silver paste has excellent electrical conductivity, which can ensure that the electrical connection between the N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 and the silver electrode film 3 is efficient and stable, which helps to reduce resistance loss and improve energy collection efficiency; and the high-temperature conductive silver paste can still maintain stable electrical conductivity under high temperature environment, and has good adhesion, which can ensure reliable connection between the thermoelectric arm and the silver electrode film 3, which helps to extend the service life of the entire energy collection structure. The N-type thermoelectric arm 1 and the P-type thermoelectric arm 2 adopt a circular thick film design, which increases the contact area between the thermoelectric arm and the heat source 5 and improves the heat absorption efficiency. At the same time, the circular thick film thermoelectric arm is combined with the flexible glass fiber substrate 4, so that the entire energy collection structure has good flexibility and adaptability, which helps to adapt to the surface of the heat source 5 of various complex shapes and improve the flexibility and efficiency of energy collection. The angle between the silver electrode film 3 at the top of the N-type thermoelectric arm 1 and the silver electrode film 3 at the bottom of the N-type thermoelectric arm 1 is an acute angle. Both ends of the thermoelectric pile are bonded with metal leads using conductive silver paste to enable the thermoelectric pile to collect thermoelectric output. In this process, an acute angle is formed between the silver electrode film 3 and the N-type thermoelectric arm 1, which helps to optimize the flow path of the current in the thermoelectric arm and reduce the transmission loss of the current in the thermoelectric arm, thereby improving the thermoelectric conversion efficiency. In the thermoelectric conversion process, heat loss is an important consideration, and reducing heat loss helps to improve the overall performance of the thermoelectric pile. Using conductive silver paste to bond the metal lead can enhance the connection strength between the thermoelectric arm and the metal lead, which not only has good conductivity, but also can withstand greater mechanical stress, ensuring the stability of the thermoelectric pile during long-term use.

[0029] In this embodiment, the thick film of the N-type thermoelectric arm is made of bismuth telluride, which has a high negative Seebeck coefficient and good conductivity. The size of the thick film of the N-type thermoelectric arm is a 3mm×3mm circle, and the thickness is about 400μm.

[0030] In this embodiment, the composition of the P-type thermoelectric arm thick film is antimony telluride, which has a high positive Seebeck coefficient and good conductivity. The size of the P-type thermoelectric arm thick film is also a 3mm×3mm circle with a thickness of about 400μm.

[0031] In this embodiment, the main component of the silver electrode film 3 is silver, which has good electrical conductivity and oxidation resistance. The size of the silver electrode film 3 is 3 mm×9 mm.

[0032] like Figure 6As shown, one side of the lattice-type flexible thermoelectric energy collection structure is tightly fitted with the curved surface of the heat source 5, and the other side is in contact with the cold end shell of the heat source 5 or exposed to the air atmosphere to form a temperature difference. The entire lattice-type flexible thermoelectric energy collection structure has the characteristics of light weight and high flexibility, so that the lattice-type flexible thermoelectric energy collection structure can adapt to various complex surfaces, including constantly changing surfaces, and can effectively collect the surface waste heat of the equipment during movement to achieve energy recycling.

[0033] When the above structure is used, PDMS can be used for flexible packaging. The role of flexible packaging is to ensure the overall mechanical strength of the structure and avoid performance degradation due to structural damage.

[0034] In a second aspect, a method for preparing a lattice-type flexible thermoelectric energy collection structure is provided, wherein the structure is prepared by the method, such as Figure 8 As shown, including: Embodiment 1: S101, cleaning, drying and cutting the flexible glass fiber substrate; illustratively, the flexible glass fiber substrate 4 is made of a thinner glass fiber cloth with a relatively smooth surface, and then the flexible glass fiber substrate 4 is ultrasonically cleaned with acetone and ethanol in turn, each cleaning time is not less than 20 minutes, and then deionized water is used to rinse off the residual organic matter on the surface of the flexible glass fiber substrate 4, and the flexible glass fiber substrate 4 is quickly dried on a heating table and then cut into appropriate sizes.

[0035] S102, on the cut flexible glass fiber substrate, prepare two patterns of silver electrode films, and dry and high-temperature anneal the two patterns of silver electrode films; illustratively, on the cut flexible glass fiber substrate 4, prepare by screen printing, such as Figure 3 and Figure 4 The silver electrode films 3 of the two patterns shown are then dried, and the thickness of the silver electrode films 3 after drying is about 30μm; the silver electrode films 3 after drying are subjected to high-temperature annealing treatment, and the annealed silver electrode films 3 have good conductivity, oxidation resistance and flexibility, and are very suitable for connecting two high-performance thermoelectric materials to improve the overall thermoelectric performance and mechanical strength of the device. Wherein, when preparing the silver electrode films 3 of the two patterns, the screen printing method is adopted, and 3~5g of 2~3μm silver powder, 0.6~1g of epoxy resin, 0.2~0.5g of polyetheramine and 0.4~0.6g of pine oil alcohol are selected; wherein, the epoxy resin is used as a binder, and the pine oil alcohol is used as a solvent to adjust the viscosity of the slurry. After the slurry is evenly stirred, a screen with a mesh size of 200 is used to print the upper and lower patterns of silver electrode film arrays through the screen printing process, as shown Figure 3 and Figure 4As shown, the thickness of the silver electrode film 3 arrays of the upper and lower patterns is 20~40μm; secondly, the printed silver electrode film 3 array is allowed to stand for 20 minutes to reduce surface stripes, placed on a heating table and slowly heated to 150°C, and dried for 20 minutes; finally, the dried silver electrode film 3 array is placed on a heating table for annealing, the heating table is slowly heated to 350°C, annealed for 60 minutes, the color of the silver film changes from light yellow to white, and finally a silver electrode film 3 is obtained.

[0036] S103, cutting the flexible glass fiber substrate along the silver electrode film after high temperature annealing to obtain two patterns of flexible glass fiber substrates; illustratively, the size of each silver electrode film 3 is 3mm×9mm, and the number of silver electrode film 3 arrays changes according to the number of thermoelectric arms. In Example 1, the number of electrode units in the silver electrode film 3 array is 20, and the overall pattern size is 18mm×55mm. Therefore, the glass fiber substrate 4 is cut to 20mm×60mm along the edge of the silver electrode film 3 pattern, and the specific size can be adjusted according to the printed silver electrode pattern and the number of thermocouples.

[0037] S104, cleaning and drying the rigid alumina substrate; illustratively, a rigid alumina substrate with a smooth and rough surface is selected, ultrasonically cleaned in acetone for 30 minutes, then rinsed in ethanol, and blown dry with a high-pressure air gun for preparing bismuth telluride thick films and antimony telluride circular thick films.

[0038] S105, preparing two kinds of thermoelectric material slurries, and printing bismuth telluride thick film and antimony telluride thick film on the rigid alumina substrate after drying, and drying and annealing the bismuth telluride thick film and antimony telluride thick film; illustratively, preparing two kinds of thermoelectric material slurries, and using customized stainless steel plates to print bismuth telluride thick film and antimony telluride thick film on the cleaned alumina substrate, and slowly drying the printed thermoelectric material thick film, the thickness of the thermoelectric thick film after drying is about 400 μm, and the two kinds of thermoelectric thick films after drying are respectively placed in a nitrogen-protected tubular furnace for annealing to improve the thermoelectric performance. When preparing the screen printing paste prepared with bismuth telluride powder, 3-5g of 500-mesh tellurium powder, 2.2-4g of 500-mesh bismuth powder, 0.1-0.3g of ethyl cellulose and 0.55-0.8g of diethylene glycol butyl ether acetate are selected; when preparing the screen printing paste prepared with antimony telluride powder, 3-5g of 500-mesh tellurium powder, 0.8-1.5g of 500-mesh bismuth powder, 1.5-2g of 500-mesh antimony powder, 0.1-0.2g of ethyl cellulose and 0.5-1.1g of diethylene glycol butyl ether acetate are selected; wherein, ethyl cellulose as a binder and the diethylene glycol butyl ether acetate as a solvent jointly determine the viscosity of the paste; after the paste is evenly stirred, a stainless steel plate with a customized pattern is used to print a circular thick film array of the thermoelectric unit, and the thickness of the circular thick film array is 350-400μm.

[0039] Subsequently, the two printed thermoelectric thick film arrays were placed in a vacuum drying oven, a vacuum environment was set and slowly heated from room temperature to 130°C for 90 minutes, and the arrays were taken out after cooling to room temperature; the dried thermoelectric thick film arrays were placed in an alumina crucible and placed in a tube furnace for annealing. The annealing process includes placing samples, sealing furnace tubes, vacuumizing, introducing nitrogen atmosphere, heating, heat preservation and cooling. Among them, nitrogen is used as a protective gas to prevent thermoelectric materials from oxidizing at high temperatures. When bismuth telluride and antimony telluride are annealed at high temperatures in the furnace tube, tellurium elements are prone to volatilization, which affects the sintering quality. Tellurium powder (0.2 g) is placed in the crucible to obtain a tellurium-rich annealing environment, which helps to inhibit the volatilization of tellurium elements in the thermoelectric thick film. For the two thermoelectric thick films, different annealing temperatures and annealing times are used to ensure the best thermoelectric performance of each. Among them, the heating time for annealing the bismuth telluride thick film is 60 minutes, the holding time is 30 minutes, and the holding temperature is 450°C. The heating time for annealing the antimony telluride thick film is 50 minutes, the holding time is 20 minutes, and the holding temperature is 400°C. After annealing, the two thermoelectric thick films are naturally cooled and taken out of the tube furnace.

[0040] S106. Polish both sides of the annealed bismuth telluride thick film and antimony telluride thick film, and bond them to two flexible glass fiber substrates with different patterns respectively through high temperature resistant conductive silver paste. Exemplarily, the annealed bismuth telluride thick film and antimony telluride circular thick film are removed from the alumina substrate to obtain an N-type thermoelectric circular thick film and a P-type thermoelectric circular thick film, and polish both sides of the thermoelectric thick film to make its surface smoother. The obtained N-type thermoelectric circular thick film and the P-type thermoelectric circular thick film are bonded to two flexible glass fiber substrates with high temperature resistant conductive silver paste to obtain the final product.

[0041] The dense lattice thermoelectric thick film structure adopted by the present invention has high output power density, is light and compact, and has good mechanical strength. It can be deformed in multiple directions, and can maintain good stability under multiple deformation actions such as bending, twisting, and stretching. The thermoelectric output and internal resistance change rate are low. The whole is prepared on a flexible substrate through a screen printing process, and has the advantages of simplicity, high efficiency, and low cost in the process flow. The preparation process improves the quality of the thick film and thermoelectric performance from the aspects of slurry ratio, printing thickness, drying time, etc. In addition, a reasonable nitrogen annealing process further improves the final performance of the thermoelectric thick film. The flexible thermoelectric energy collector designed by the present invention has a large space utilization rate, can be tightly attached to a complex curved surface within a certain curvature, is easy to disassemble, and can be attached without loss. The substrate is made of high-temperature resistant glass fiber and bonded with high-temperature conductive silver paste, which can be used for thermoelectric energy collection in a wide temperature range.

[0042] Embodiment 2: The difference from the first embodiment is that this embodiment uses a single N / P type thermoelectric material Bi 2 Te 2.7 Se 0.3 and Bi 0.5 Sb 1.5 Te 3 As the raw material of thermoelectric powder in screen printing slurry, adding excess tellurium powder optimizes the sintering quality during annealing, and generally has a higher Seebeck coefficient. During the printing process, two thermoelectric films are obtained by screen printing process, and the printing and drying are repeated several times to reach the target thickness. The thermoelectric circular thick film and the silver electrode are connected by high-temperature conductive silver paste to finally form a flexible thermoelectric device. The flexible thermoelectric energy collection structure finally formed in Example 2 is the same as that in Example 1 in structure and function.

[0043] S101, cleaning, drying and cutting the flexible glass fiber substrate; illustratively, the flexible glass fiber substrate 4 is made of a thinner glass fiber cloth with a relatively smooth surface, and then the flexible glass fiber substrate 4 is ultrasonically cleaned with acetone and ethanol in turn, each cleaning time is not less than 20 minutes, and then deionized water is used to rinse off the residual organic matter on the surface of the flexible glass fiber substrate 4, and the flexible glass fiber substrate 4 is quickly dried on a heating table and then cut into appropriate sizes.

[0044] S102, on the cut flexible glass fiber substrate, prepare two patterns of silver electrode films, and dry and high-temperature anneal the two patterns of silver electrode films; illustratively, on the cut flexible glass fiber substrate 4, prepare by screen printing, such as Figure 3 and Figure 4 The silver electrode films 3 of the two patterns shown are then dried, and the thickness of the silver electrode films 3 after drying is about 30μm; the silver electrode films 3 after drying are subjected to high-temperature annealing treatment, and the annealed silver electrode films 3 have good conductivity, oxidation resistance and flexibility, and are very suitable for connecting two high-performance thermoelectric materials to improve the overall thermoelectric performance and mechanical strength of the device. Wherein, when preparing the silver electrode films 3 of the two patterns, the screen printing method is adopted, and 3~5g of 2~3μm silver powder, 0.6~1g of epoxy resin, 0.2~0.5g of polyetheramine and 0.4~0.6g of pine oil alcohol are selected; wherein, the epoxy resin is used as a binder, and the pine oil alcohol is used as a solvent to adjust the viscosity of the slurry. After the slurry is evenly stirred, a screen with a mesh size of 200 is used to print the upper and lower patterns of silver electrode film arrays through the screen printing process, as shown Figure 3 and Figure 4 As shown, the thickness of the silver electrode film 3 arrays of the upper and lower patterns is 20~40μm; secondly, the printed silver electrode film 3 array is allowed to stand for 20 minutes to reduce surface stripes, placed on a heating table and slowly heated to 150°C, and dried for 20 minutes; finally, the dried silver electrode film 3 array is placed on a heating table for annealing, the heating table is slowly heated to 350°C, annealed for 60 minutes, the color of the silver film changes from light yellow to white, and finally a silver electrode film 3 is obtained.

[0045] S103, cutting the flexible glass fiber substrate along the silver electrode film after high temperature annealing to obtain two patterns of flexible glass fiber substrates; illustratively, the size of each silver electrode film 3 is 3mm×9mm, and the number of silver electrode film 3 arrays changes according to the number of thermoelectric arms. In Example 1, the number of electrode units in the silver electrode film 3 array is 20, and the overall pattern size is 18mm×55mm. Therefore, the glass fiber substrate 4 is cut to 20mm×60mm along the edge of the silver electrode film 3 pattern, and the specific size can be adjusted according to the printed silver electrode pattern and the number of thermocouples.

[0046] S104, ball milling treatment is performed on N-type / P-type thermoelectric powders to reduce the particle size of the two powders, so as to form a thermoelectric film with lower porosity after printing and to sinter more fully during annealing; N-type thermoelectric powder (Bi 2 Te 2.7 Se 0.3) and P-type thermoelectric powder (Bi 0.5 Sb 1.5 Te 3 ) 20g each for ball milling, add 5g of alcohol. Use zirconium dioxide ball milling beads with diameters of 8mm, 5mm and 3mm and ball milling jars of the same material. The number ratio of the three sizes of ball milling beads is 1:1:2, and the total volume ratio of ball milling beads to powder is 5:1. Grind at 350rpm for more than 12 hours; after the ball milling is completed, take out the powder and ball milling beads in the ball milling jar, wash them with alcohol and collect them in a container; put the container containing thermoelectric powder and alcohol into a vacuum drying oven and dry it at 60 degrees for 120 minutes. Finally, two kinds of refined thermoelectric powders that can be used are obtained. The particle size of the thermoelectric powder after ball milling is less than 2μm; S105. Prepare two thermoelectric printing pastes respectively, use a customized screen printing screen to print bismuth telluride and antimony telluride films on a flexible glass fiber substrate printed with silver electrodes, slowly dry the printed thermoelectric material film, repeat the printing and drying steps many times to increase the thickness of the thermoelectric film, and finally form a thermoelectric thick film of about 200μm. After drying, the two thermoelectric thick films are placed in a nitrogen-protected tubular furnace for annealing to improve the thermoelectric performance. Prepare a mixed solution for screen printing paste, the solution composition is: diethylene glycol butyl ether acetate 7~10g, ethyl cellulose 1~2g, dibutyl phthalate 1~2g, Tween 80 (0.1g). Among them, diethylene glycol butyl ether acetate is a solvent, ethyl cellulose is a binder, dibutyl phthalate is a plasticizer, and Tween 80 is a dispersant. The prepared solution was stirred at 80°C for 4 hours on a magnetic stirrer at a speed of 300 rpm until completely dissolved and then set aside; the N-type screen printing slurry includes: 3.5-5g Bi2Te2.7Se0.3 powder and 0.3-0.8g diethylene glycol butyl ether acetate solution. The P-type screen printing slurry includes: 3.5-5g Bi0.5Sb1.5Te3 powder and 0.3-0.8g diethylene glycol butyl ether acetate solution; after the slurry is stirred evenly, a screen printing screen with a customized pattern is used to repeatedly print a thermoelectric circular thick film array on the obtained silver electrode, with a thickness of about 200μm-250μm; the two printed thermoelectric thick film arrays are placed in a vacuum drying oven, a vacuum environment is set and slowly heated from room temperature to 130°C for 90 minutes, and the thermoelectric thick film array is taken out after cooling to room temperature; the dried thermoelectric thick film array is placed in an alumina crucible and placed in a tubular furnace for annealing. The steps of the annealing treatment are placing the sample, sealing the furnace tube, vacuum treatment, introducing nitrogen atmosphere, heating, heat preservation and cooling. Among them, nitrogen is used as a protective gas to prevent the thermoelectric material from being oxidized at high temperature. When bismuth telluride and antimony telluride are annealed at high temperature in the furnace tube, the tellurium element is easy to volatilize, which affects the sintering quality. 0.2g of tellurium powder is placed in the crucible to obtain a tellurium-rich annealing environment, which helps to inhibit the volatilization of tellurium elements in the thermoelectric thick film. For the two thermoelectric thick films, different annealing temperatures and annealing times are used to ensure that their respective thermoelectric properties are optimal. Among them, the heating time for annealing the bismuth telluride thick film is 60 minutes, the heat preservation time is 30 minutes, and the heat preservation temperature is 450°C. The heating time for annealing the antimony telluride thick film is 50 minutes, the heat preservation time is 20 minutes, and the heat preservation temperature is 400°C. The two thermoelectric thick films are naturally cooled after annealing and taken out of the tube furnace. Finally, the obtained product was bonded to the silver electrode pattern through a high temperature resistant conductive silver paste to obtain the final product, and the performance of the obtained lattice-type flexible thermoelectric energy harvesting structure was tested, such as Figure 7 As shown, the output performance of the prepared lattice-type flexible thermoelectric energy harvesting structure was tested. Figure 7The output voltage curve of the lattice-type flexible thermoelectric energy harvesting structure under continuous heating and insulation, as well as the internal resistance change curve after 0-800 bending in different directions, are shown. The results show that the prepared lattice-type flexible thermoelectric energy harvesting structure has stable thermoelectric output and mechanical properties, and can efficiently and continuously collect thermoelectric energy from complex surfaces and waste heat on the surface of moving parts.

[0047] In summary, the lattice-type flexible thermoelectric energy collection structure proposed in the present invention relates to the field of flexible thermoelectric energy storage, and can be applied to the surface waste heat energy collection of various places such as human body, vehicles, aircraft, large equipment, etc., and can achieve the purpose of driving micro-power consumption equipment in combination with energy management circuit. The lattice-type flexible thermoelectric energy collection structure proposed in the present invention structurally includes a bipolar thermoelectric conversion unit, a flexible glass fiber substrate and an electrical connection unit. The main component of the flexible glass fiber substrate is silicon dioxide, which has good high temperature resistance and flexibility. The main component of the electrical connection unit is silver, which has good stability and conductivity. It is attached to the surface of the flexible substrate and fits the two ends of the thermocouple to achieve the purpose of electrical connection and reduce the contact resistance. The dense lattice-type thermoelectric thick film structure adopted in the present invention has high output power density, is light and compact, and has good mechanical strength. The thermoelectric device has a large space utilization rate, can be tightly attached to a complex curved surface within a certain curvature, is easy to disassemble, can be non-destructively attached, and has high thermoelectric performance and practical application value.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A lattice-type flexible thermoelectric energy collection structure, characterized in that: include: A flexible glass fiber substrate (4) having two layers; A thermoelectric unit is disposed between two layers of the flexible glass fiber substrate (4), and a plurality of the thermoelectric units are arranged along the length of the flexible glass fiber substrate (4), with a zigzag thermoelectric pile formed between the plurality of the thermoelectric units; Silver electrode films (3) are provided on the top and bottom of the thermoelectric unit, and the silver electrode films (3) are used for electrical connection of the thermoelectric unit; The flexible glass fiber substrate (4) located at the bottom layer is used to adhere to the surface of the heat source (5), and the flexible glass fiber substrate (4) located at the top layer is in contact with the cold end area of ​​the heat source (5).

2. The lattice-type flexible thermoelectric energy collection structure according to claim 1, characterized in that: The multiple thermoelectric units are connected in series; Each thermoelectric unit comprises an N-type thermoelectric arm (1) and a P-type thermoelectric arm (2), and the tops of the N-type thermoelectric arm (1) and the P-type thermoelectric arm (2) are connected via a silver electrode film (3); The bottoms of the N-type thermoelectric arm (1) and the P-type thermoelectric arm (2) are connected to the N-type thermoelectric arm (1) and the P-type thermoelectric arm (2) in another adjacent thermoelectric unit via a silver electrode film (3).

3. The lattice-type flexible thermoelectric energy collection structure according to claim 2, characterized in that: The N-type thermoelectric arm (1) and the P-type thermoelectric arm (2) are both circular thick films, and are electrically connected to the silver electrode film (3) via high-temperature conductive silver paste.

4. The lattice-type flexible thermoelectric energy collection structure according to claim 2 or 3, characterized in that: The angle between the silver electrode film (3) at the top of the N-type thermoelectric arm (1) and the silver electrode film (3) at the bottom of the N-type thermoelectric arm (1) is an acute angle.

5. The lattice-type flexible thermoelectric energy collection structure according to claim 1, characterized in that: Both ends of the thermopile are bonded with metal leads using conductive silver paste so that the thermopile can collect thermoelectric output.

6. A method for preparing a lattice-type flexible thermoelectric energy collection structure according to any one of claims 1 to 5, characterized in that: include: Clean, dry and cut the flexible fiberglass substrate; On the cut flexible glass fiber substrate, preparing two patterns of silver electrode films, and performing drying and high-temperature annealing treatment on the two patterns of silver electrode films; Cutting the flexible glass fiber substrate along the silver electrode film after high temperature annealing to obtain flexible glass fiber substrates with two patterns; The rigid alumina substrate is cleaned and dried; Prepare two kinds of thermoelectric material slurries, print bismuth telluride thick film and antimony telluride thick film on the rigid alumina substrate after drying, and dry and anneal the bismuth telluride thick film and antimony telluride thick film; Both sides of the annealed bismuth telluride thick film and antimony telluride thick film are polished and respectively bonded to flexible glass fiber substrates with two patterns through high temperature resistant conductive silver paste.

7. The method for preparing a lattice-type flexible thermoelectric energy collection structure according to claim 6, characterized in that: The silver electrode films of two patterns are prepared, specifically comprising: The screen printing method was used, and 3-5 g of 2-3 μm silver powder, 0.6-1 g of epoxy resin, 0.2-0.5 g of polyetheramine, and 0.4-0.6 g of pineneol were selected; Among them, epoxy resin is used as a binder and pinene alcohol is used as a solvent to adjust the viscosity of the slurry. After the slurry is evenly stirred, a screen with a mesh size of 200 is used to print the silver electrode film arrays with upper and lower patterns through a screen printing process.

8. The method for preparing the lattice-type flexible thermoelectric energy collection structure according to claim 7, characterized in that: The thickness of the silver electrode thin film arrays of the upper and lower patterns is 20-40 μm.

9. The method for preparing a lattice-type flexible thermoelectric energy collection structure according to claim 6, characterized in that: The preparation of two thermoelectric material slurries specifically includes: When preparing the screen printing paste prepared by bismuth telluride powder, 3-5g of 500-mesh telluride powder, 2.2-4g of 500-mesh bismuth powder, 0.1-0.3g of ethyl cellulose and 0.55-0.8g of diethylene glycol butyl ether acetate are selected; When preparing the screen printing paste prepared by antimony telluride powder, 3-5g of 500-mesh tellurium powder, 0.8-1.5g of 500-mesh bismuth powder, 1.5-2g of 500-mesh antimony powder, 0.1-0.2g of ethyl cellulose and 0.5-1.1g of diethylene glycol butyl ether acetate are selected; Wherein, the ethyl cellulose as a binder and the diethylene glycol butyl ether acetate as a solvent are used to adjust the viscosity of the slurry; After the slurry is stirred evenly, a circular thick film array of thermoelectric units is printed using a stainless steel plate with a customized pattern.

10. The method for preparing a lattice-type flexible thermoelectric energy collection structure according to claim 9, characterized in that: The thickness of the circular thick film array is 350-400 μm.

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