A novel high-temperature semiconductor thermoelectric generator and a method for manufacturing the same

Abstract

The application relates to a novel material of a semiconductor thermoelectric generator and a preparation method of the device, which comprises providing a pair of novel matching materials, a preparation method of the corresponding materials and electrode selection of the corresponding materials. Based on the above thermoelectric materials and electrode materials, the thermoelectric device is directly welded by using a hot-press welding mode, one-step welding of upper and lower electrode sheets of the thermoelectric device is completed, the operation is simple, and large-scale production is suitable. The thermoelectric device prepared by the application can be long-term and stable in operation at a medium temperature of about 500 DEG C, has relatively high performance and is suitable for use as a medium-temperature thermoelectric device.

Description

Technical Field

[0001] This invention relates to a novel semiconductor thermoelectric power generation device and its preparation method, belonging to the field of thermoelectric power generation energy conversion device preparation. Background Technology

[0002] Modern society is developing towards greater intelligence and environmental friendliness, leading to an ever-increasing demand for energy. Currently, a large portion of electricity still comes from the conversion of coal, oil, or natural gas. However, due to incomplete conversion, energy conversion efficiency is low, and a significant portion of the heat is directly discharged as waste heat, such as through boiler exhaust and vehicle emissions. Thermoelectric power generation utilizes the Seebeck effect to directly convert heat energy into electrical energy, thus avoiding energy waste to a certain extent. Furthermore, in fields such as deep space and deep sea exploration, solar power generation is not very effective, making isotope nuclear batteries based on thermoelectric power generation a good alternative. By providing a stable temperature difference to thermoelectric devices through isotope radiation, they can provide a stable supply of electrical energy. Additionally, because some isotopes have long half-lives, nuclear batteries have a long operating life, which is of great significance for lunar and Martian exploration.

[0003] Thermoelectric devices are devices that convert heat energy into electrical energy. They are mainly composed of semiconductor materials and are characterized by having no moving parts, small size, long lifespan, no noise, and no maintenance. The most crucial element is the thermoelectric material itself. Generally, a thermoelectric device contains both n-type and p-type thermoelectric materials. Currently, PbTe, GeTe, and CoSb3 are among the most researched medium-temperature thermoelectric materials. However, for medium-temperature thermoelectric devices, PbTe-based devices are the most mature. However, Pb is toxic and poses significant harm to the environment and organisms, making it unsuitable for large-scale use. The high-performance GeTe thermoelectric material is unsuitable for medium-temperature thermoelectric devices due to its significant phase transition. CoSb3 is also unsuitable for medium- and high-temperature thermoelectric devices due to its instability and fragility. Similar problems exist with other thermoelectric materials. Therefore, developing new materials to fabricate high-performance medium-temperature thermoelectric devices is a growing trend. Summary of the Invention

[0004] To address the above problems, this invention provides a pair of novel thermoelectric materials for fabricating high-performance mid-temperature thermoelectric devices, which can provide stable electrical energy output at mid-temperature, while also exhibiting stable structure, non-toxic composition, and high device performance.

[0005] The specific technical solution of this invention is as follows:

[0006] On one hand, the present invention provides a novel semiconductor thermoelectric power generation device, the power generation device comprising an n-type thermoelectric material and a p-type thermoelectric material, characterized in that the n-type thermoelectric material is composed of Mg.3.2-x A x Sb 2-y-z Bi y B z Where A is at least one of Y, Mn, Ba, Ca, and Sc, and B is at least one of Te and Se; x = 0.05-0.2, y = 0-2, z = 0-0.1;

[0007] The p-type thermoelectric material has the composition Sb2Si2- z M z Te6 or (Sb2Si2- z M z Te6)N w The second phase doped material, wherein M is at least one of Ge, Zn, and Mn, N is Te or Si2Te3, z = 0.001-0.1, and w = 0-0.2.

[0008] On the other hand, the present invention provides a method for preparing the above-mentioned semiconductor thermoelectric power generation device, characterized in that the method includes the following steps:

[0009] A. Weigh the metal materials according to the specified ratio and place them in a ball mill jar. Prepare n-type thermoelectric material Mg by high-energy ball milling. 3-x A x Sb 2-y B y The powder is covered with electrode powder on both sides during hot pressing to form an electrode. The thermoelectric material is pressed at the pressing temperature that gives the best performance of the actual thermoelectric material.

[0010] B. Weigh the metal material according to the ratio and place it in a ball mill jar. Prepare p-type thermoelectric material powder by ball milling and annealing. When pressing the thermoelectric material into a sheet, cover both the top and bottom sides with electrode powder to form an electrode. The thermoelectric material pressing temperature is the pressing temperature at which the actual thermoelectric material has the best performance.

[0011] C. Cut the n-type and p-type components to the required size using wire cutting or dicing machines to ensure that the upper and lower surfaces of each particle are electrode materials.

[0012] D. Prepare two ceramic plates covered with electrode sheets. Apply solder paste or solder evenly to the ceramic plates with copper electrodes. Apply the paste evenly to both the upper and lower ceramic plates.

[0013] E. Place the cut P-type and N-type particles evenly and alternately on one of the ceramic plates' electrode plates, then cover it with another ceramic plate, ensuring that the electrodes fit together perfectly.

[0014] F. Carefully place the device processed in step E into a graphite mold, press it firmly with the upper and lower pressure heads of the mold, and then place it in a hot press for welding. After welding, the semiconductor thermoelectric generator is obtained.

[0015] The order of steps A and B above is not important.

[0016] Preferably, the ball milling time for the n-type thermoelectric material is 10 min to 1 h; the ball mill is a three-dimensional rotating high-energy ball mill or a high-energy ball mill with a speed of 600 rpm or higher.

[0017] Preferably, in step A, the n-type material is subjected to a pressure of 50MPa-80MPa during tableting, the tableting temperature is 600℃-800℃, and the holding time is 2min-5min.

[0018] Preferably, in step B, the pressure applied to the p-type material during tableting is 40MPa-60MPa, the tableting temperature is 450℃-550℃, and the holding time is 5min-10min.

[0019] Preferably, the electrode layer used in the n-type thermoelectric material is one or more of the following metal layers: Fe, Ni, Cr, Mo, CoMo, Ti, Au, NiAu, and TiAu, and the electrode melting point of the corresponding thermoelectric arm is higher than the optimal pressing temperature of the thermoelectric material. The electrode layer used in the p-type thermoelectric material is one or more of the following metal layers: Fe, Ni, Cr, CoMo, Ag, AgCu, and TiAu.

[0020] Preferably, the electrode thickness of the thermoelectric material is 1mm-2mm during pressing. The required amount of electrode powder is calculated based on the density.

[0021] Preferably, the thermoelectric material during hot pressing can be electrode material / thermoelectric material / electrode material, or electrode material / thermoelectric material / electrode material / thermoelectric material / electrode material, or the number of layers can be further increased to achieve rapid mass production of thermoelectric arms.

[0022] Preferably, when the thermoelectric device is welded in a hot press furnace, the pressure applied is 1MPa-10MPa. The welding temperature is 450℃-550℃, and the welding time is 20min-60min.

[0023] Preferably, the ceramic plate is alumina or aluminum nitride; the thickness of the ceramic plate is 0.1 mm to 1 mm; the electrode sheet on the surface of the ceramic plate is prepared by magnetron sputtering and electrodeposition; the thickness of the electrode sheet is 0.05 mm to 0.5 mm; and the electrode sheet is a copper electrode.

[0024] Preferably, the welding material is solder paste or CuAg alloy solder sheet; the solder paste is silver solder paste, tin paste or CuAgSn solder paste, or is formed by mixing nano-metal powder with an organic solvent.

[0025] Preferably, the particle size of the nano-metal powder is 20nm-100nm; the organic solvent is at least one of ethanol, DBE, anti-whitening agent, acrylic resin and CN methylpyrrolidone.

[0026] The present invention also provides an application of the above-mentioned semiconductor thermoelectric generator, which can be used in radioisotope thermoelectric generators, automobile exhaust waste heat recovery power generation devices, household stove wall heat collection and outdoor portable thermoelectric generators.

[0027] Beneficial effects

[0028] 1. This invention provides a novel medium-temperature thermoelectric material with characteristics such as high temperature resistance, high performance, non-volatile properties at high temperatures, and structural stability.

[0029] 2. The p-type thermoelectric material provided by this invention can be synthesized quickly and efficiently, and is suitable for mass production.

[0030] 3. The high-energy ball milling method provided by this invention is fast and efficient in preparing medium-temperature thermoelectric materials, saving more time than traditional preparation methods and ordinary ball milling methods, and shortening the preparation time by at least 10 times.

[0031] 4. The p-type thermoelectric material prepared by this invention has a higher ZT value, and its PF is also 20% higher than that of Sb2Si2Te6.

[0032] 5. This invention provides a simple and rapid electrode preparation method, which uses hot-press welding to directly weld the upper and lower electrode sheets of the thermoelectric device in one step. The operation is simple and conducive to mass production and application.

[0033] 6. The novel thermoelectric power generation device provided by this invention overcomes the problems of easy breakage, low stability, low performance, and toxicity and volatility of medium and high temperature devices during use by using novel thermoelectric materials. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of thermoelectric materials and electrode plates;

[0035] Figure 2 This is a schematic diagram of a single thermoelectric arm of the present invention;

[0036] Figure 3 It is a ceramic plate with copper electrodes;

[0037] Figure 4 This is a schematic diagram of a welding mold;

[0038] Figure 5 Output power of Sb2Si2Te6 thermoelectric material after Ge doping;

[0039] Figure 6 The energy conversion efficiency of the device prepared in the embodiments of the present invention;

[0040] Figure 7 The output power of the device prepared in the embodiments of the present invention;

[0041] Wherein: 1 is graphite mold; 2 is electrode material; 3 is thermoelectric material; 4 is graphite indenter; 5 is copper electrode; 6 is alumina ceramic plate. Detailed Implementation

[0042] The following are specific embodiments of the present invention, but the invention is by no means limited to these embodiments.

[0043] Example

[0044] The alumina ceramic plate of this invention has a thickness of 0.3 mm to 0.5 mm, and the P-type semiconductor material is Sb₂Si. 1.94 Ge 0.06 Te6, the N-type semiconductor material is Mg 3.15 Y 0.05 Sb 1.5 Bi 0.49 Te 0.01 .

[0045] The method for fabricating the semiconductor thermoelectric generator provided by this invention is as follows:

[0046] (1) Preparation of p-type thermoelectric material Sb2Si 1.94 Ge 0.06 Te6:

[0047] First, according to the Sb2Si ratio 1.94 Ge 0.06 Te6 weighs an appropriate amount of high-purity metal material and places it in a ball mill jar. Then, it is ball-milled for 2 hours. After that, the ball-milled powder is vacuum-sealed with a quartz tube. The sealed tube is placed in a high-temperature furnace and annealed at 550°C for 3 days. The calcined powder is then crushed and hot-pressed.

[0048] First, place a 1mm thick Fe electrode material in a graphite mold and compact it with a pressure head. Then, add an appropriate amount of Sb₂Si. 1.94 Ge 0.06 Te6 thermoelectric material powder is compacted, and then the same electrode material is poured in, such as... Figure 1 As shown. Then, hot pressing is performed, holding at 450℃ for 5 minutes under a pressure of 50MPa. The resulting block is then cut into pieces as shown. Figure 2 The particles shown.

[0049] (2) Preparation of n-type thermoelectric material Mg 3.15 Y 0.05 Sb 1.5 Bi 0.49 Te 0.01

[0050] Weigh an appropriate amount of granules or powder into a high-energy ball mill jar according to the proportion, and ball mill for 30 min. After ball milling, take out the powder in an argon-filled glove box, and in the same way as loading p-type materials (1), first place a 1 mm thick Fe electrode material in the graphite mold, compact it with a pressure head, then put in an appropriate amount of n-type thermoelectric material powder, compact it, and then pour in the same electrode material. After compaction, under a pressure of 50 MPa, first anneal at 400℃ for 10 min, then press it into a sheet, press and hold it at 800℃ for 2 min-5 min, or directly hold it at 800℃ for 10 min. Cut the obtained block into the shape shown below. Figure 2 The particles shown.

[0051] (3) Device fabrication

[0052] Nano-silver powder was mixed with an organic solution and then evenly coated onto the copper electrodes of the upper and lower ceramic plates. Cut particles were then placed on the lower ceramic plate in an n / p interval. The upper ceramic plate was then placed on top, and the mixture was placed in a graphite mold and kept at 450℃ and 1MPa pressure for 40 minutes.

[0053] The device prepared in this invention has a maximum output power of 1.8W under a temperature difference of 500K. Figure 6 The energy conversion efficiency is 5.6%. Figure 5 Furthermore, its performance and structure remain stable after multiple measurements.

[0054] Comparative Example

[0055] The p-type thermoelectric material in the above embodiment is replaced with Sb2Si2Te6, and the other contents are the same as in the embodiment.

[0056] like Figure 5 As shown, by doping Sb2Si2Te6 with 0.06% Ge, its output power density was significantly improved, which has a significant effect on improving the output power of the device.

[0057] Within the scope of the technical field of the invention, without departing from the technical solution of the invention, several equivalent substitutions or obvious modifications can be made, and all of these should be considered to fall within the protection scope of the invention.

Claims

1. A novel semiconductor thermoelectric power generation device, the power generation device comprising an n-type thermoelectric material and a p-type thermoelectric material, characterized in that, The n-type thermoelectric material is composed of Mg 3.2-x A x Sb 2-y-z Bi y B z Where A is at least one of Y, Mn, Ba, Ca, and Sc, and B is at least one of Te and Se; x = 0.05-0.2, y = 0-2, z = 0-0.1; The p-type thermoelectric material is composed of Sb₂Si. 2-z M z Te6 or (Sb2Si) 2-z M z Te6)N w The second phase doped material, wherein M is at least one of Ge, Zn, and Mn, N is Te or Si2Te3, z = 0.001-0.1, and w = 0-0.

2.

2. A method for fabricating the semiconductor thermoelectric generator according to claim 1, characterized in that, The method includes the following steps: A. Weigh the metal materials according to the ratio and place them in a ball mill jar. After ball milling, obtain the powder of n-type thermoelectric material. Then, perform hot pressing and sheet pressing. During sheet pressing, the electrode layer is hot-pressed onto the upper and lower surfaces of the n-type thermoelectric material. After hot pressing, n-type component is obtained. B. Weigh the metal materials according to the ratio and place them in a ball mill jar. After ball milling, anneal the powder to obtain the p-type thermoelectric material. Then, hot press the powder into sheets. During pressing, the electrode layer is hot-pressed onto the upper and lower surfaces of the p-type thermoelectric material. After hot pressing, a p-type component is obtained. C. Cut the n-type and p-type components to the required size, ensuring that each particle is covered with an electrode layer on both the upper and lower surfaces. D. Prepare two ceramic plates covered with electrode plates, and apply the welding material evenly to the electrode plates of the two ceramic plates. E. Place the cut P-type and N-type particles evenly and alternately on one of the ceramic plates' electrode plates, then cover it with another ceramic plate, ensuring that the electrodes fit together perfectly. F. Place the device processed in step E into a mold and press it with the upper and lower pressure heads of the mold. Then place it in a hot press for welding. After welding, the semiconductor thermoelectric generator is obtained. Steps A and B are not in any particular order.

3. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, The ball milling time for the n-type thermoelectric material is 10 minutes to 1 hour; the ball mill is a three-dimensional rotating high-energy ball mill or a high-energy ball mill with a speed of 600 rpm or higher.

4. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, In step A, the pressure applied to the n-type thermoelectric material during pressing is 50MPa-80MPa, the pressing temperature is 400℃-800℃, and the holding time is 2min-10min. In step B, the pressure applied to the p-type thermoelectric material during pressing is 40MPa-60MPa, the pressing temperature is 450℃-550℃, and the holding time is 5min-10min.

5. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, In step F, when the thermoelectric device is welded in the hot press, the pressure applied is 1MPa-10MPa, the welding temperature is 450℃-550℃, and the welding time is 20min-60min.

6. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, In step A, the electrode layer used in the n-type thermoelectric material is one or more of the following metal layers: Fe, Ni, Cr, Mo, CoMo, Ti, Au, NiAu, and TiAu. In step B, the electrode layer used in the p-type thermoelectric material is one or more of the following metal layers: Fe, Ni, Cr, CoMo, Ag, AgCu, and TiAu. The thickness of any electrode layer is 0.1mm-1mm.

7. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, The ceramic plate is made of alumina or aluminum nitride; the thickness of the ceramic plate is 0.1 mm to 1 mm; the electrode sheet on the surface of the ceramic plate is prepared by magnetron sputtering and electrodeposition; the thickness of the electrode sheet is 0.05 mm to 0.5 mm; the electrode sheet is a copper electrode.

8. The method for preparing a semiconductor thermoelectric power generation device according to claim 2, characterized in that, The welding material is solder paste or CuAg alloy solder sheet; the solder paste is silver solder paste, tin paste or CuAgSn solder paste, or it is formed by mixing nano-metal powder with an organic solvent.

9. The method for preparing a semiconductor thermoelectric power generation device according to claim 8, characterized in that, The particle size of the nano-metal powder is 20nm-100nm; the organic solvent is at least one of ethanol, DBE, anti-whitening agent, acrylic resin and CN methylpyrrolidone.

10. An application of the semiconductor thermoelectric generator according to claim 1 or the semiconductor thermoelectric generator prepared by the method of any one of claims 2-8, characterized in that, The thermoelectric device is used in radioisotope thermoelectric generators, automobile exhaust waste heat recovery power generation devices, household stove wall heat collection, and portable outdoor thermoelectric generators.

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