Preparation method of segmented thermoelectric device for electronic refrigeration

Abstract

The invention discloses a segmented thermoelectric device for electronic refrigeration and a preparation method thereof, the segmented thermoelectric device comprises an N-type thermoelectric single leg and a P-type thermoelectric single leg, the N-type thermoelectric single leg is sintered by a three-step method, and the chemical composition of the N-type thermoelectric single leg is represented as Ag-Fe / Fe < 90 > Sb < 10 > / Mg < 3.2 > Bi < 1.5 > Sb < 0.498 > Te < 0.002 > Cu < 0.01 > / Fe < 90 > Sb < 10 > / Bi < 2 > Te < 2.694 > Se < 0.3 > I < 0.006 > / Fe < 90 > Sb < 10 > / Ag-Fe; the P-type thermoelectric single leg is sintered by a one-step method, and the chemical composition of the P-type thermoelectric single leg is represented as Ag-Fe / Fe < 90 > Sb < 10 > / Bi < 0.07 > Ge < 0.9 > Te / Fe < 90 > Sb < 10 > / Ag-Fe. Research results show that the two N-type thermoelectric materials, namely Mg < 3.2 > Bi < 1.5 > Sb < 0.498 > Te < 0.002 > Cu < 0.01 > and Bi < 2 > Te < 2.694 > Se < 0.3 > I < 0.006 >, have good matching performance with the P-type thermoelectric material Bi < 0.07 > Ge < 0.9 > Te in thermoelectric performance, the open-circuit voltage, the current and the output power of the finally prepared segmented thermoelectric device can be greatly improved through the synergistic effect of the N-type thermoelectric materials and the P-type thermoelectric material Bi < 0.07 > Ge < 0.9 > Te, and then the strict requirement of an actual scene for precise temperature control can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of thermoelectric refrigeration devices, and in particular relates to a method for preparing a segmented thermoelectric device for electronic refrigeration. Background Art

[0002] Thermoelectric cooling devices achieve efficient energy conversion by virtue of the unique properties of thermoelectric materials. They operate based on the Peltier effect and abandon the use of traditional refrigerants. They are environmentally friendly and noiseless, and have no moving parts inside, which greatly reduces the probability of mechanical failure and reduces maintenance costs. They have high application value in cold chain, electronics, medical and other fields with extremely high requirements for temperature control, and can effectively solve complex temperature control problems. For example, in the cold chain industry, they accurately maintain a low temperature environment to ensure the freshness and quality of food and medicine, in the electronics field, they provide stable heat dissipation guarantee for precision electronic equipment to extend the service life of the equipment, and in the medical field, they meet the strict temperature requirements of medical equipment and provide reliable support for medical diagnosis and treatment. As global energy demand continues to grow, the requirements for temperature control and energy efficiency are becoming increasingly stringent. The research, innovation and promotion of thermoelectric cooling devices have become increasingly important. Increasing R&D investment can not only promote the innovative development of energy and related industries, but also have great significance for achieving sustainable energy development, promoting energy conservation and emission reduction, and actively responding to environmental challenges.

[0003] Thermoelectric cooling devices work based on the Peltier effect, that is, when current passes through a closed loop formed by connecting two different conductors or semiconductors, heat absorption or heat release occurs at the two connection points, thereby realizing heat transfer and achieving the effect of cooling or heating. The device is generally composed of multiple P-type and N-type semiconductor elements connected in thermal parallel and electrically in series. When the refrigeration is working, the DC power supply is turned on, the current flows through the device, and the electrons undergo energy conversion at the junction of different materials. The connection point on one side absorbs heat, thereby achieving cooling and refrigeration of the local area; the connection point on the other side releases heat and transfers the absorbed heat. The performance of the device is affected by many factors such as the thermoelectric properties of the material (such as Seebeck coefficient, electrical conductivity, thermal conductivity, etc.) and the device structure (including shape, size, connection method, interface material, etc.). Common thermoelectric materials include bismuth antimony alloy, silicon-germanium alloy, tellurium-bismuth alloy, etc. Reasonable design of the structure can improve the cooling efficiency.

[0004] There are many types of thermoelectric cooling materials, among which bismuth telluride and its alloys are one of the most widely used materials in the field of thermoelectric cooling. Its optimal operating temperature is below 450K. It exhibits excellent thermoelectric performance in the low temperature range and can efficiently realize the conversion of heat and electrical energy to achieve a cooling effect. Because of this, it frequently appears in many daily and professional scenes, such as small freezers, which accurately maintain a low temperature environment to ensure the proper storage of items; thermostats that always control the temperature stability; in the cooling process of electronic devices, it effectively dissipates heat to ensure the normal operation of equipment, and also plays a key role in professional fields such as medicine, nuclear physics, and vacuum technology.

[0005] The energy conversion efficiency of thermoelectric devices is usually an important indicator to measure the performance of thermoelectric devices. It is calculated by testing the open circuit voltage, open circuit current and output power of thermoelectric devices and combining the efficiency formula Q c is the cooling capacity, P out is the output power, and the conversion efficiency of the thermoelectric device can be calculated.

[0006] Thermoelectric cooling materials such as Bi2Te3 and Mg3Sb2 are primarily selected for their excellent thermoelectric properties. The quality of thermoelectric materials is often measured by the thermoelectric figure of merit T = S 2 Using σT / κ as a scale, the two show high ZT values ​​in a specific temperature range. Bi2Te3 is a classic thermoelectric material. In the range of low to medium temperature, the Seebeck coefficient and conductivity are balanced, the electron carrier concentration is high, and the temperature difference power conversion efficiency is fast. At the same time, the emerging Mg3Sb2 and Bi2Te3 are adapted to similar operating temperature ranges and can be used as segmented single legs.

[0007] Bi2Te3 is suitable for working at room temperature and below, and is especially suitable for cooling electronic equipment, small refrigeration equipment and other scenarios. Mg3Sb2 can also be used for low-temperature device operation through doping and other processes. When preparing thermoelectric devices, the above two materials are compatible with metal electrodes, buffer materials, etc., and are suitable for welding and interface treatment. After being built into an efficient thermoelectric circuit, the performance is intact. In terms of process maturity, Bi2Te3 has melt growth, mechanical alloying, chemical vapor deposition and other methods, which makes its microscopic properties easy to control; the solid-state reaction method of Mg3Sb2 is also more conducive to large-scale mass production. At the same time, the reserves of raw materials such as bismuth, tellurium, magnesium, and antimony are not scarce, which reduces the cost of thermoelectric devices in terms of raw materials. Summary of the invention

[0008] In view of this, an object of the present invention is to provide a segmented thermoelectric device for electronic refrigeration and a preparation method thereof.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A first aspect of the present invention provides a segmented thermoelectric device for electronic refrigeration, the segmented thermoelectric device comprising an N-type thermoelectric single leg and a P-type thermoelectric single leg, wherein the chemical composition of the N-type thermoelectric single leg is represented by Ag-Fe / Fe 90 Sb 10 / Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 / Fe 90 Sb 10 / Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe, the N-type thermoelectric single leg is composed of a first N-type thermoelectric material, a second N-type thermoelectric material, and a buffer layer and a weldable connection layer respectively compounded on both sides and in the middle of the first N-type thermoelectric material and the second N-type thermoelectric material, wherein Fe 90 Sb 10 As buffer layer, Ag-Fe is weldable connection layer, Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 Bi2Te is the first N-type thermoelectric material 2.694 Se 0.3 I 0.006 It is a second N-type thermoelectric material.

[0011] The chemical composition of the P-type thermoelectric single leg is represented by Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe 90 Sb 10 / Ag-Fe, the P-type thermoelectric single leg is composed of a P-type thermoelectric material, a buffer layer and a weldable connection layer respectively compounded on both sides of the P-type thermoelectric material; wherein Fe 90 Sb 10 is a buffer layer, Ag-Fe is a weldable connection layer, Bi 0.07 Ge 0.9 Te is a P-type thermoelectric material.

[0012] Preferably, in the N-type thermoelectric single leg, the thickness of the first N-type thermoelectric material is 2-4 mm, the thickness of the second N-type thermoelectric material is 0.5-1 mm, the thickness of the buffer layer is 0.1-0.3 mm, and the thickness of the weldable connection layer is 0.4-0.8 mm.

[0013] Preferably, in the P-type thermoelectric single leg, the thickness of the P-type thermoelectric material is 2-4 mm, the thickness of the buffer layer is 0.1-0.3 mm, and the thickness of the weldable connection layer is 0.4-0.8 mm.

[0014] Preferably, the size of the N-type thermoelectric single leg is (1-3) mm×(1-3) mm×(3-5) mm.

[0015] Preferably, the size of the P-type thermoelectric single leg is (1-3) mm×(1-3) mm×(3-5) mm.

[0016] Preferably, the segmented thermoelectric device also includes: a copper electrode and an alumina ceramic substrate, the copper electrode and the alumina ceramic substrate are bonded together by a DBC process, the thickness of the copper electrode is 0.1-0.3 mm, the thickness of the alumina ceramic substrate is 0.6-0.8 mm, and the size is 5-5.5 mm×5-5.5 mm.

[0017] A second aspect of the present invention provides a method for preparing the above-mentioned segmented thermoelectric device for electronic refrigeration, comprising the following steps:

[0018] S1. Preparation of N-type thermoelectric single leg:

[0019] S11, Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The powder is loaded into a graphite mold and compacted, and then hot-pressed and sintered to obtain a block 1;

[0020] S12, Bi2Te 2.694 Se 0.3 I 0.006 The powder is loaded into a graphite mold and compacted, and then hot-pressed and sintered to obtain block 2;

[0021] S13, Ag-Fe powder, Fe 90 Sb 10 The powder, block 1 and block 2 are loaded into a graphite mold in layers according to the composition structure of the N-type thermoelectric single leg and compacted;

[0022] S14, placing the loaded graphite mold in a vacuum hot pressing device for hot pressing and sintering to obtain a block sample;

[0023] S15, cutting and forming: cutting the block sample to obtain an N-type thermoelectric single leg of a target size;

[0024] S2. Preparation of P-type thermoelectric single leg:

[0025] S21, Ag-Fe powder, Bi0.07 Ge 0.9 Te powder, Fe 90 Sb 10 The powders are loaded into a graphite mold and compacted in the order of the P-type thermoelectric single-leg composition structure;

[0026] S22, placing the loaded graphite mold in a spark plasma sintering device to perform spark plasma sintering to obtain a cylindrical sample;

[0027] S23, cutting the cylindrical sample to obtain a P-type thermoelectric single leg of a target size;

[0028] S3, gold plating, welding and assembly:

[0029] The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are gold-plated and welded, and then assembled together with a copper electrode and an alumina ceramic substrate to obtain a segmented thermoelectric device.

[0030] Preferably, in step S11, the hot pressing sintering temperature is 700-780K, the sintering pressure is 750-800Kg, and the sintering time is 15-35min. Since hot pressing sintering equipment usually uses kilograms (Kg) as the pressure display unit, kilograms (Kg) are used as the pressure measurement unit in the present invention.

[0031] Preferably, in step S12, the hot pressing sintering temperature is 500-580K, the sintering pressure is 600-680Kg, and the sintering time is 15-35min.

[0032] Preferably, in step S14, the hot pressing sintering temperature is 400-550K, the sintering pressure is 400-480Kg, and the sintering time is 60-70min.

[0033] Preferably, in step S22, the spark plasma sintering temperature is 700-780K, and the sintering time is 6-15 minutes.

[0034] Preferably, the process conditions for the cutting and forming are: cutting the sample using an electric spark wire with a wire diameter of 0.35 to 0.45 mm.

[0035] Preferably, cleaning is required after the cutting and forming, and the cleaning conditions are: ultrasonic cleaning with ethanol, and the cleaning time is 20 to 30 minutes.

[0036] Preferably, in step S3, the gold plating is performed using a micro ion sputtering apparatus through cold plating technology; the welding uses tin-lead solder, and the welding time is 20 to 25 seconds.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The present invention uses simulation to clarify the differences in cooling capacity between different materials. At the same time, it strictly follows the screening principle of thermoelectric figure of merit (zT) and then evaluates the thermoelectric conversion efficiency of the materials to select the P-type thermoelectric material Bi with excellent performance. 0.07 Ge 0.9 Te, which shows unique advantages and potential in thermoelectric performance. Based on the scientific screening principle of tolerance factor S, Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 and Bi2Te 2.694 Se 0.3 I 0.006 These two N-type thermoelectric materials form an N-type segmented single leg. 90 Sb 10 is a buffer layer, and Ag-Fe is a weldable connection layer. 90 Sb 10 It has unique properties, specifically: first, its coefficient of thermal expansion (CTE) is not much different from the CTE of the first N-type thermoelectric material and the second N-type thermoelectric material selected. Under the temperature condition of 373K, its CTE value is 15.3×10 -6 K -1 ; Second, the barrier layer Fe 90 Sb 10 The degree of thermal diffusion is small. In the N-type integral layered material, the barrier layer of the middle layer can connect the first N-type thermoelectric material and the second N-type thermoelectric material, and can also increase the stability of the N-type integral layered material, and can effectively prevent the thermal diffusion of the "Sb" element in the first and second N-type thermoelectric materials. The barrier layers on both sides, in addition to the same functions of the barrier layer of the middle layer, can also prevent the thermal diffusion of the "Fe" element in the solderable layer. The solderable layer has many unique and important properties and functions. In terms of properties, first, the coefficient of thermal expansion (CTE) of the solderable layer is not much different from the CTE of the selected first N-type thermoelectric material and the second N-type thermoelectric material. At 373K, its CTE value is 18.3×10 -6 K -1 ; Second, the electrical conductivity of the solderable layer is very high, reaching 3.17×10 7 cm -3 ; Thirdly, the "Ag" in the solderable layer can form an intermetallic compound Ag Sn with the "Sn" in the solder, and the CTE of this compound is 19.3×10 -6 K -1; Fourthly, the "Fe" in the solderable layer does not react with the solder and exists in the joint in a single substance. In terms of function, the solderable layer can enhance the stability of welding, allowing the thermoelectric material to be stably welded to the copper electrode.

[0039] The results showed that the above Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 and Bi2Te 2.694 Se 0.3 I 0.006 Two N-type thermoelectric materials and P-type Bi 0.07 Ge 0.9 Te material has good matching in thermoelectric performance. Through the synergistic effect of the two, the open-circuit voltage, current and output power of the final thermoelectric device are greatly improved, which can meet the strict requirements of actual scenarios for high-precision, stable and reliable device cooling and precision temperature control technology for precise temperature control. It provides a better cooling solution for precision low-temperature scenarios such as high-precision semiconductor lasers and quantum computing, thereby enhancing its practicality and market competitiveness in various scenarios, and has significant industrial value and innovative significance.

[0040] (2) The existing thermoelectric devices have great differences in sintering temperatures of different N-type materials, which makes it difficult for these materials to be successfully sintered together, which directly limits the thermoelectric cooling devices to achieve high open circuit voltage, high current and high output power. To address this problem, the present invention has made innovations at the design level, abandoning the traditional commercial N-type single thermoelectric material Bi2Te 2.694 Se 0.3 I 0.006 , it is designed into segmented first and second N-type thermoelectric materials, and they are connected by a barrier layer, which effectively improves the open circuit voltage, current and output power of the thermoelectric cooling device. In terms of process, the present invention adopts a three-step method to prepare an N-type thermoelectric single leg, overcoming the technical difficulty of the existing segmented thermoelectric single leg that fails to be manufactured due to the large difference in sintering temperature of each material.

[0041] (3) The preparation method of the present invention has many outstanding advantages, which are specifically manifested as follows: the present invention changes the traditional commercial N-type single thermoelectric material into a segmented design and uses a barrier layer for connection. This innovative technology improves the open circuit voltage, current and output power of the thermoelectric cooling device, providing new ideas and directions for the development of the industry; in terms of process operation, the present invention adopts a three-step method to prepare an N-type thermoelectric single leg, which has a simple process, simple operation, and easy to master, effectively simplifies the manufacturing process and greatly improves production efficiency. Moreover, the method of the present invention effectively solves the technical problem of production failure caused by excessive differences in sintering temperatures of different materials, has good compatibility with a variety of materials, can adapt to the sintering requirements of different types of N-type materials, and shows strong adaptability. At the same time, because the method of the present invention has clear steps, stable parameters, high repeatability, and can ensure the consistency of product quality, it is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A schematic flow chart of a method for preparing a segmented thermoelectric device for electronic refrigeration provided by the present invention;

[0044] Figure 2 Schematic diagram of a segmented N-type thermoelectric single leg and a P-type thermoelectric single leg in a segmented thermoelectric device prepared in Example 1;

[0045] Figure 3 Schematic diagram of an N-type thermoelectric single leg and a P-type thermoelectric single leg in the thermoelectric device prepared in Comparative Example 1;

[0046] Figure 4 The performance measurement results of the segmented thermoelectric device prepared in Example 1 are as follows: (a) open circuit voltage; (b) on-resistance; (c) open circuit current; (d) output power;

[0047] Figure 5 The performance measurement results of the segmented thermoelectric device prepared in Example 2: (a) open circuit voltage; (b) on-resistance; (c) open circuit current; (d) output power;

[0048] Figure 6 The performance measurement results of the segmented thermoelectric device prepared in Example 3 are as follows: (a) open circuit voltage; (b) on-resistance; (c) open circuit current; (d) output power;

[0049] Figure 7 The performance measurement results of the thermoelectric device prepared in Comparative Example 1 are: (a) open circuit voltage; (b) on-resistance; (c) open circuit current; and (d) output power. DETAILED DESCRIPTION

[0050] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are provided to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may also be implemented in other embodiments without these specific details.

[0051] Example 1

[0052] See also Figure 1 A method for preparing a segmented thermoelectric device for electronic refrigeration, the segmented thermoelectric device comprising a P-type thermoelectric single leg and an N-type thermoelectric single leg, comprising the following steps:

[0053] 1. Preparation of thermoelectric single-leg materials:

[0054] 1. Preparation of N-type thermoelectric single-leg materials;

[0055] (1) Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The powder is evenly compacted into a graphite abrasive tool with a diameter of 10.0 mm, where Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The height of the thermoelectric material is 2.4 mm, and then hot pressing is performed under a pressure of 775 kg to make the sintering temperature reach 750 K, and the heat preservation time is 20 min to obtain a block 1;

[0056] (2) Bi2Te 2.694 Se 0.3 I 0.006 The powder is evenly compacted into a graphite mold with a diameter of 10.0 mm, where Bi2Te 2.694 Se 0.3 I 0.006 The height of the thermoelectric material is 0.6 mm, and then hot pressing sintering is carried out under a pressure of 643 kg, the sintering temperature is 550 K, and the holding time is 20 min to obtain block 2;

[0057] (3) The obtained block 1, block 2, and Fe as a buffer layer 90 Sb 10 , and the Ag-Fe as the welding layer is divided into Ag-Fe / Fe 90 Sb10 / Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 / Fe 90 Sb 10 / Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then hot-pressed sintered at a pressure of 450 kg, with a sintering temperature of 500 K and a holding time of 65 min to obtain a block sample;

[0058] 2. Preparation of P-type thermoelectric single-leg materials:

[0059] Bi 0.07 Ge 0.9 Te powder, Fe as buffer layer 90 Sb 10 , and Ag-F as a weldable connection layer in the order of segments Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then the obtained powder was subjected to spark plasma (densification) sintering at a pressure of 775 kg, a sintering temperature of 750 K, and a holding time of 8 mins to obtain a cylindrical sample;

[0060] 2. Cutting thermoelectric materials:

[0061] (1) The block sample obtained above was cut into rectangular blocks with a size of 1.6 mm × 1.6 mm × 3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain an N-type thermoelectric single leg (see Figure 2 );

[0062] (2) The cylindrical sample obtained above was cut into a rectangular block with a size of 1.6×1.6×3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain a highly dense cylindrical sample (diameter 10.0 mm×height 3.0 mm), namely the P-type thermoelectric single leg (see Figure 2 );

[0063] 3. Gold plating and welding:

[0064] The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are plated with gold by cold plating technology using a micro ion sputtering device, and then soldered with tin-lead solder;

[0065] 4. Assembly and independent testing:

[0066] A copper electrode with a thickness of 0.2 mm and an alumina ceramic substrate with a thickness of 0.635 mm were bonded by a direct copper bonding (DBC) process and then assembled to obtain a segmented thermoelectric device with a 2×2 structure.

[0067] A platform was built in the laboratory to conduct independent performance tests on the segmented thermoelectric devices. The temperature of the N-type thermoelectric single leg, i.e. the cold end, was set to 18.4°C, and the temperature of the P-type thermoelectric single leg, i.e. the hot end, was set to 33.4°C. The temperature difference was 15K, and the test was carried out for 60 seconds. The results are shown in Figure 4 .

[0068] Depend on Figure 4 (a)- Figure 4 (d) The results show that the maximum open circuit voltage of the segmented thermoelectric device prepared in this embodiment is 19.9261 mV, the average internal resistance is 0.670165 Ω, the maximum open circuit current is 2.40393 A, and the maximum output power is 18.30924 mW.

[0069] Example 2

[0070] A method for preparing a segmented thermoelectric device for electronic refrigeration, wherein the segmented thermoelectric device comprises a P-type thermoelectric single leg and an N-type thermoelectric single leg, comprising the following steps:

[0071] 1. Preparation of thermoelectric single-leg materials:

[0072] 1. Preparation of N-type thermoelectric single-leg materials;

[0073] (1) Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The powder is evenly compacted into a graphite abrasive tool with a diameter of 10.0 mm, where Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The height of the thermoelectric material is 2.4 mm, and then hot pressing is performed under a pressure of 750 kg to make the sintering temperature reach 700 K, and the heat preservation time is 15 min to obtain a block 1;

[0074] (2) Bi2Te 2.694 Se 0.3 I 0.006The powder is evenly compacted into a graphite mold with a diameter of 10.0 mm, where Bi2Te 2.694 Se 0.3 I 0.006 The height of the thermoelectric material is 0.6 mm, and then hot pressing is performed under a pressure of 600 kg, the sintering temperature is 500 K, and the holding time is 15 min to obtain block 2;

[0075] (3) The obtained block 1, block 2, and Fe as a buffer layer 90 Sb 10 , and the Ag-Fe as the welding layer is divided into Ag-Fe / Fe 90 Sb 10 / Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 / Fe 90 Sb 10 / Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then hot-pressed sintered under a pressure of 400 kg, with a sintering temperature of 400 K and a holding time of 60 min to obtain a block sample;

[0076] 2. Preparation of P-type thermoelectric single-leg materials:

[0077] Bi 0.07 Ge 0.9 Te powder, Fe as buffer layer 90 Sb 10 , and Ag-F as a weldable connection layer in the order of segments Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then the obtained powder was subjected to spark plasma (densification) sintering at a pressure of 775 kg, a sintering temperature of 750 K, and a holding time of 8 mins to obtain a cylindrical sample;

[0078] 2. Cutting thermoelectric materials:

[0079] (1) The block sample obtained above was cut into a rectangular block with a size of 1.6 mm × 1.6 mm × 3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain an N-type thermoelectric single leg;

[0080] (2) The cylindrical sample obtained above was cut into a rectangular block with a size of 1.6×1.6×3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain a highly dense cylindrical sample (diameter 10.0 mm×height 3.0 mm), i.e., a P-type thermoelectric single leg;

[0081] 3. Gold plating and welding:

[0082] The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are plated with gold by cold plating technology using a micro ion sputtering device, and then soldered with tin-lead solder;

[0083] 4. Assembly and independent testing:

[0084] A copper electrode with a thickness of 0.2 mm and an alumina ceramic substrate with a thickness of 0.635 mm were bonded by a direct copper bonding (DBC) process and then assembled to obtain a segmented thermoelectric device with a 2×2 structure.

[0085] A platform was built in the laboratory to conduct independent performance tests on the segmented thermoelectric devices. The temperature of the N-type thermoelectric single leg, i.e. the cold end, was set to 18.4°C, and the temperature of the P-type thermoelectric single leg, i.e. the hot end, was set to 33.4°C. The temperature difference was 15K, and the test was carried out for 60 seconds. The results are shown in Figure 5 .

[0086] Depend on Figure 5 (a)- Figure 5 (d) The results show that the maximum open circuit voltage of the segmented thermoelectric device prepared in this embodiment is 10.40892 mV, the average internal resistance is 0.670163 Ω, the maximum open circuit current is 1.66571 A, and the maximum output power is 10.92737 mW.

[0087] Example 3

[0088] A method for preparing a segmented thermoelectric device for electronic refrigeration, wherein the segmented thermoelectric device comprises a P-type thermoelectric single leg and an N-type thermoelectric single leg, comprising the following steps:

[0089] 1. Preparation of thermoelectric single-leg materials:

[0090] 1. Preparation of N-type thermoelectric single-leg materials;

[0091] (1) Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01The powder is evenly compacted into a graphite abrasive tool with a diameter of 10.0 mm, where Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The height of the thermoelectric material is 2.4 mm, and then hot pressing is performed under a pressure of 800 kg to make the sintering temperature reach 780 K, and the heat preservation time is 35 min to obtain a block 1;

[0092] (2) Bi2Te 2.694 Se 0.3 I 0.006 The powder is evenly compacted into a graphite mold with a diameter of 10.0 mm, where Bi2Te 2.694 Se 0.3 I 0.006 The height of the thermoelectric material is 0.6 mm, and then hot pressing sintering is carried out under a pressure of 680 kg, the sintering temperature is 580 K, and the holding time is 35 min to obtain block 2;

[0093] (3) The obtained block 1, block 2, and Fe as a buffer layer 90 Sb 10 , and the Ag-Fe as the welding layer is divided into Ag-Fe / Fe 90 Sb 10 / Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 / Fe 90 Sb 10 / Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then hot-pressed sintered at a pressure of 480 kg, with a sintering temperature of 550 K and a holding time of 70 min to obtain a block sample;

[0094] 2. Preparation of P-type thermoelectric single-leg materials:

[0095] Bi 0.07 Ge 0.9 Te powder, Fe as buffer layer 90 Sb 10 , and Ag-F as a weldable connection layer in the order of segments Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then the obtained powder was subjected to spark plasma (densification) sintering at a pressure of 775 kg, a sintering temperature of 750 K, and a holding time of 8 mins to obtain a cylindrical sample;

[0096] 2. Cutting thermoelectric materials:

[0097] (1) The block sample obtained above was cut into a rectangular block with a size of 1.6 mm × 1.6 mm × 3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain an N-type thermoelectric single leg;

[0098] (2) The cylindrical sample obtained above was cut into a rectangular block with a size of 1.6×1.6×3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain a highly dense cylindrical sample (diameter 10.0 mm×height 3.0 mm), i.e., a P-type thermoelectric single leg;

[0099] 3. Gold plating and welding:

[0100] The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are plated with gold by cold plating technology using a micro ion sputtering device, and then soldered with tin-lead solder;

[0101] 4. Assembly and independent testing:

[0102] A copper electrode with a thickness of 0.2 mm and an alumina ceramic substrate with a thickness of 0.635 mm were bonded by a direct copper bonding (DBC) process and then assembled to obtain a segmented thermoelectric device with a 2×2 structure.

[0103] A platform was built in the laboratory to conduct independent performance tests on the segmented thermoelectric devices. The temperature of the N-type thermoelectric single leg, i.e. the cold end, was set to 18.4°C, and the temperature of the P-type thermoelectric single leg, i.e. the hot end, was set to 33.4°C. The temperature difference was 15K, and the test was carried out for 60 seconds. The results are shown in Figure 6 .

[0104] Depend on Figure 6 (a)- Figure 6 (d) The results show that the maximum open circuit voltage of the segmented thermoelectric device prepared in this embodiment is 9.8814 mV, the average internal resistance is 0.670164 Ω, the maximum open circuit current is 1.84439 A, and the maximum output power is 11.50606 mW.

[0105] Comparative Example 1

[0106] A method for preparing a thermoelectric device based on a single unlayered N-type material comprises the following steps:

[0107] 1. Preparation of thermoelectric single-leg materials:

[0108] 1. Preparation of N-type thermoelectric single-leg materials;

[0109] (1) Bi2Te 2.694 Se 0.3 I 0.006 Powder, Fe as buffer layer 90 Sb 10 , and the Ag-Fe as the welding layer is in the undivided order of Ag-Fe / Fe 90 Sb 10 Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then hot-pressed sintered at a pressure of 643 kg, with a sintering temperature of 550 K and a holding time of 20 min to obtain a block sample;

[0110] 2. Preparation of P-type thermoelectric single-leg materials:

[0111] Bi 0.07 Ge 0.9 Te powder, Fe as buffer layer 90 Sb 10 , and Ag-F as a weldable connection layer in the order of segments Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe 90 Sb 10 / Ag-Fe was compacted into a graphite mold with a diameter of 10.0 mm, and then the obtained powder was subjected to spark plasma (densification) sintering at a pressure of 775 kg, a sintering temperature of 750 K, and a holding time of 8 mins to obtain a cylindrical sample;

[0112] 2. Cutting thermoelectric materials:

[0113] (1) The block sample obtained above was cut into rectangular blocks with a size of 1.6 mm × 1.6 mm × 3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain an N-type thermoelectric single leg (see Figure 3 );

[0114] (2) The cylindrical sample obtained above was cut into a rectangular block with a size of 1.6×1.6×3.0 mm by wire electrospark cutting, and then ultrasonically cleaned with ethanol for 20 min to obtain a highly dense cylindrical sample (diameter 10.0 mm×height 3.0 mm), namely the P-type thermoelectric single leg (see Figure 3 ):

[0115] 3. Gold plating and welding:

[0116] The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are plated with gold by cold plating technology using a micro ion sputtering device, and then soldered with tin-lead solder;

[0117] 4. Assembly and independent testing:

[0118] A copper electrode with a thickness of 0.2 mm and an alumina ceramic substrate with a thickness of 0.635 mm were bonded by a direct copper bonding (DBC) process and then assembled to obtain a segmented thermoelectric device with a 2×2 structure.

[0119] A platform was built in the laboratory to conduct independent performance tests on the segmented thermoelectric devices. The temperature of the N-type thermoelectric single leg, i.e. the cold end, was set to 18.4°C, and the temperature of the P-type thermoelectric single leg, i.e. the hot end, was set to 33.4°C. The temperature difference was 15K, and the test was carried out for 60 seconds. The results are shown in Figure 7 .

[0120] Depend on Figure 7 (a)- Figure 7 (d) The results show that the maximum open circuit voltage of the thermoelectric device prepared in this comparative example is 7.529567 mV, the average internal resistance is 0.70751 Ω, the maximum open circuit current is 0.90934 A, and the maximum output power is 6.15369 mW.

[0121] The performance results of the thermoelectric devices prepared in the above Examples 1-3 and Comparative Example 1 are compared, and the specific results are shown in Table 1.

[0122] Table 1.

[0123] Implementation Name Maximum open circuit voltage (mV) Average internal resistance (Q) Maximum open circuit current (mA) Maximum output power (mW) Comparative Example 1 7.529567 0.70751 0.90934 6.15369 Example 1 19.9261 0.670165 2.40393 18.30924 Example 2 10.40892 0.670163 1.66571 10.92737 Example 3 9.88154 0.670164 1.84439 11.50606

[0124] From the results in Table 1, it can be seen that the highest open circuit voltage, open circuit current, and output power in the performance measurement results of the segmented thermoelectric devices prepared in Examples 1-3 of the present invention are all higher than those in Comparative Example 1, and the average internal resistance is lower than that in Comparative Example 1. That is, the performance of the thermoelectric devices based on layered N-type materials (two N-type materials) prepared in Examples 1-3 of the present invention is significantly improved compared with the thermoelectric device based on a single unlayered N-type material prepared in Comparative Example 1.

[0125] By comparing the results of Example 1 and Example 2-3, it can be seen that the maximum open circuit voltage, open circuit current, and output power results of the segmented thermoelectric device performance measurement results obtained in Example 2-3 are all lower than those in Comparative Example 1. This is due to a significant reduction or increase in the sintering temperature and pressure. Furthermore, it can be seen that if the sintering temperature and pressure are further too low or too high, it will lead to an inability to sinter densely, resulting in increased resistance, and causing irreversible consequences such as inability to conduct electricity. In addition, the thermoelectric single leg obtained in this case will face mechanical deformation, including irreversible reactions such as cracks and twisting, which will result in the inability to be assembled into a thermoelectric device.

[0126] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. A segmented thermoelectric device for electronic cooling, comprising an N-type thermoelectric single leg and a P-type thermoelectric single leg, characterized in that: The chemical composition of the N-type thermoelectric single leg is represented by Ag-Fe / Fe 90 Sb 10 / Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 / Fe 90 Sb 10 / Bi2Te 2.694 Se 0.3 I 0.006 / Fe 90 Sb 10 / Ag-Fe, the N-type thermoelectric single leg is composed of a first N-type thermoelectric material, a second N-type thermoelectric material, and a buffer layer and a weldable connection layer respectively compounded on both sides and in the middle of the first N-type thermoelectric material and the second N-type thermoelectric material, wherein Fe 90 Sb 10 As buffer layer, Ag-Fe is weldable connection layer, Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 Bi2Te is the first N-type thermoelectric material 2.694 Se 0.3 I 0.006 is a second N-type thermoelectric material; The chemical composition of the P-type thermoelectric single leg is represented by Ag-Fe / Fe 90 Sb 10 / Bi 0.07 Ge 0.9 Te / Fe 90 Sb 10 / Ag-Fe, the P-type thermoelectric single leg is composed of a P-type thermoelectric material, a buffer layer and a weldable connection layer respectively compounded on both sides of the P-type thermoelectric material; wherein Fe 90 Sb 10 is a buffer layer, Ag-Fe is a weldable connection layer, Bi 0.07 Ge 0.9 Te is a P-type thermoelectric material.

2. The segmented thermoelectric device for electronic refrigeration according to claim 1, characterized in that: In the N-type thermoelectric single leg, the thickness of the first N-type thermoelectric material is 2-4 mm, the thickness of the second N-type thermoelectric material is 0.5-1 mm, the thickness of the buffer layer is 0.1-0.3 mm, and the thickness of the weldable connection layer is 0.4-0.8 mm.

3. The segmented thermoelectric device for electronic refrigeration according to claim 1, characterized in that: In the P-type thermoelectric single leg, the thickness of the P-type thermoelectric material is 2-4 mm, the thickness of the buffer layer is 0.1-0.3 mm, and the thickness of the weldable connection layer is 0.4-0.8 mm.

4. The segmented thermoelectric device for electronic refrigeration according to claim 1, characterized in that: The size of the N-type thermoelectric single leg is (1-3) mm×(1-3) mm×(3-5) mm; the size of the P-type thermoelectric single leg is (1-3) mm×(1-3) mm×(3-5) mm.

5. A method for preparing a segmented thermoelectric device for electronic refrigeration according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Preparation of N-type thermoelectric single leg: S11, Mg 3.2 Bi 1.5 Sb 0.498 Te 0.002 Cu 0.01 The powder is loaded into a graphite mold and compacted, and then hot-pressed and sintered to obtain a block 1; S12, Bi2Te 2.694 Se 0.3 I 0.006 The powder is loaded into a graphite mold and compacted, and then hot-pressed and sintered to obtain block 2; S13, Ag-Fe powder, Fe 90 Sb 10 The powder, block 1 and block 2 are loaded into a graphite mold in layers according to the composition structure of the N-type thermoelectric single leg and compacted; S14, placing the loaded graphite mold in a vacuum hot pressing device for hot pressing and sintering to obtain a block sample; S15, cutting the block sample to obtain an N-type thermoelectric single leg of a target size; S2. Preparation of P-type thermoelectric single leg: S21, Ag-Fe powder, Bi 0.07 Ge 0.9 Te powder, Fe 90 Sb 10 The powders are loaded into a graphite mold and compacted in the order of the P-type thermoelectric single-leg composition structure; S22, placing the loaded graphite mold in a spark plasma sintering device to perform spark plasma sintering to obtain a cylindrical sample; S23, cutting the cylindrical sample to obtain a P-type thermoelectric single leg of a target size; S3, gold plating, welding and assembly: The obtained N-type thermoelectric single leg and P-type thermoelectric single leg are gold-plated and welded, and then assembled together with a copper electrode and an alumina ceramic substrate to obtain a segmented thermoelectric device.

6. The method for preparing a segmented thermoelectric device according to claim 1, characterized in that: In step S11, the hot pressing sintering temperature is 700-780K, the sintering pressure is 750-800Kg, and the sintering time is 15-35min; in step S12, the hot pressing sintering temperature is 500-580K, the sintering pressure is 600-680Kg, and the sintering time is 15-35min.

7. The method for preparing a segmented thermoelectric device according to claim 1, characterized in that: In step S14, the hot pressing sintering temperature is 400-550K, the sintering pressure is 400-480Kg, and the sintering time is 60-70min.

8. The method for preparing a segmented thermoelectric device according to claim 1, characterized in that: The cutting and forming process conditions are: using a diamond cutting wire with a wire diameter of 0.35 to 0.45 mm to cut the sample.

9. The method for preparing a segmented thermoelectric device according to claim 1, characterized in that: After the cutting and forming, cleaning is required, and the cleaning conditions are: ultrasonic cleaning with ethanol, and the cleaning time is 20 to 30 minutes.

10. The method for preparing a segmented thermoelectric device according to claim 1, characterized in that: The copper electrode has a thickness of 0.1 to 0.3 mm, the alumina ceramic substrate has a thickness of 0.6 to 0.8 mm, and a size of 5 to 5.5 mm×5 to 5.5 mm.

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