CN-122028637-A - High-reliability thermoelectric device with foam connection layer and preparation method thereof

Abstract

The invention discloses a high-reliability thermoelectric device with a foam connection layer and a preparation method thereof, and the high-reliability thermoelectric device comprises the following steps of S1, respectively preparing thermoelectric material powder and barrier layer material powder, paving the barrier layer material powder at a high-temperature end of the thermoelectric material powder, forming an integrated thermoelectric material layer-barrier layer composite block body through a sintering process, S2, cutting and processing a thermoelectric material layer-barrier layer composite structure obtained in the step S1 to obtain at least one initial thermoelectric arm with a barrier layer, S3, welding a metal foam material with a communicated porous structure on the surface of the barrier layer of the initial thermoelectric arm, wherein the equivalent Young modulus of the metal foam material is lower than that of the thermoelectric material layer and the barrier layer, so as to obtain a functional thermoelectric arm with the foam connection layer, and S4, welding corresponding metal electrodes or a substrate covered with the metal electrodes at two ends of the functional thermoelectric arm, so as to obtain the thermoelectric device. The device has good high-temperature reliability.

Inventors

• JIANG JUN
• Jiang Zhoumin
• TAN XIAOJIAN
• ZHANG ZONGWEI

Assignees

• 中国科学院宁波材料技术与工程研究所

Dates

Publication Date

20260512

Application Date

20260107

Claims (10)

1. 1. A method of fabricating a high reliability thermoelectric device incorporating a foam tie layer, comprising the steps of: S1, respectively preparing thermoelectric material powder and barrier layer material powder, paving the barrier layer material powder at the high-temperature end of the thermoelectric material powder, and forming an integrated thermoelectric material layer-barrier layer composite block body through a sintering process; S2, cutting the thermoelectric material layer-barrier layer composite block obtained in the step S1 to obtain at least one initial thermoelectric arm with a barrier layer; s3, welding a metal foam material with a communicated porous structure on the surface of the barrier layer of the initial thermoelectric arm, wherein the equivalent Young' S modulus of the metal foam material is lower than that of the thermoelectric material layer and the barrier layer, so as to obtain a functional thermoelectric arm with a foam connection layer; And S4, assembling the high-temperature end and the low-temperature end of the functional thermoelectric arm with the corresponding metal electrodes or the substrate coated with the metal electrodes in a die, and then welding and connecting the high-temperature end and the low-temperature end of the functional thermoelectric arm with the corresponding metal electrodes to form the thermoelectric device.
2. 2. The method of claim 1, wherein the thermoelectric material powder is at least one selected from the group consisting of PbTe-based thermoelectric materials, geTe-based thermoelectric materials, half-Heusler alloy system materials, skutterudite-based materials.
3. 3. The method according to claim 1, wherein the barrier layer powder is at least one of a metal powder, a metal-based compound powder, a nitride ceramic powder, a carbide ceramic powder, and an oxide ceramic powder, which are chemically stable for blocking an element diffusion reaction.
4. 4. The method of claim 1, wherein the sintering process is induction sintering, hot press sintering, or spark plasma sintering.
5. 5. The method according to claim 1, wherein the metal foam material is at least one of a transition metal foam material, a light metal foam material, an alloy foam material of a transition metal, and an alloy foam material of a light metal, which have stable properties under medium and high temperature conditions.
6. 6. The method of claim 1, wherein the foam tie layer has a porosity of 20% -80%.
7. 7. The method according to claim 1, wherein the soldering in the step S3 is at least one of diffusion soldering, and metal-based soldering, wherein the solder used in the soldering is at least one of tin-based soldering, lead-based soldering, copper-based soldering, and silver-based soldering, and the high-temperature end soldering in the step S4 is at least one of diffusion soldering, and metal-based soldering.
8. 8. The method according to claim 1 or 7, further comprising performing at least one of surface modification treatment of plating, electroless plating, and spray plating on the surface of the metal foam material before step S3, wherein a plating material used for the plating, electroless plating, or spray plating is at least one of a metal capable of generating a wetting effect with the solder used for soldering in step S3, the solder used for high temperature end soldering in step S4, and a compound thereof.
9. 9. A high reliability thermoelectric device incorporating a foam tie layer, prepared by the method of any one of claims 1-8.
10. 10. The high reliability thermoelectric device incorporating a foam connection layer according to claim 9, wherein the high reliability thermoelectric device is a medium temperature thermoelectric power generation module, and the operating hot side temperature is not lower than 700K.

Description

High-reliability thermoelectric device with foam connection layer and preparation method thereof Technical Field The invention relates to the technical field of thermoelectric devices, in particular to a high-reliability thermoelectric device with a foam connection layer and a preparation method thereof. Background The thermoelectric device realizes direct conversion between heat energy and electric energy based on Seebeck effect, has the advantages of no moving parts, reliable work, environmental friendliness and the like, and has wide application prospect in the fields of industrial waste heat recovery, aerospace deep space exploration, radioisotope power supply, distributed energy system and the like. In recent years, with the continuous improvement of the performance of thermoelectric materials, particularly, a medium-temperature thermoelectric material system represented by PbTe obtains a higher thermoelectric figure of merit (zT) in a temperature range of 600-800K, and the initial output power and the energy conversion efficiency of a thermoelectric device reach the basic requirements of engineering application. However, the problem of long-term stability of thermoelectric devices under actual service conditions is increasingly pronounced as compared to the increase in material properties. In medium and high temperature conditions, thermoelectric devices are often required to withstand large temperature gradients and frequent start-up and shut-down conditions, and repeated thermal cycling resulting therefrom can introduce significant thermal stresses between functional layers within the device. Because of the obvious difference of the thermoelectric material, the barrier layer, the metal electrode and the welding layer in the aspects of thermal expansion coefficient, young modulus, plastic deformation capacity and the like, free thermal strain mismatch is inevitably generated at an interface in the thermal cycle process, and the free thermal strain mismatch is further developed into interface shear stress and peeling stress. In the prior art, to improve service reliability of thermoelectric devices, research is mainly focused on improving chemical stability of interfaces, for example, by introducing a barrier layer between thermoelectric materials and metal electrodes to inhibit element diffusion, avoid brittle phase generation and reduce contact resistivity. Common barrier material designs are screened by chemical stability and mechanical property matching. The method improves the chemical compatibility and the initial electrical property of the interface to a certain extent, but the design thought is still based on an integrated structure, and each interface layer generally pursues unification of the electrical property, the mechanical property and the chemical inertness, so that the problem that the interface layer cannot be combined with the material cannot be avoided, and the problem is hindered for searching the proper material. The inventors have further studied and found that it is difficult to avoid the continuous accumulation of thermal stress at the interface even in the case where the interface resistance is low and chemical reactions are effectively suppressed by the conventional rigid interface structure. When the number of thermal cycles is increased or the temperature difference is further increased, microcracks are easily generated at the interface and gradually spread, and finally, the blocking layer is cracked, the welding layer is in fatigue failure or even the thermoelectric arm is dropped off, which is shown as irreversible attenuation of the output power and the efficiency of the device. This shows that it is difficult to solve the reliability problem of thermoelectric devices under medium-high temperature thermal cycling conditions from the mechanical aspect, depending on the optimization of the interface material composition alone. Therefore, from the aspect of device structure design, a novel thermoelectric device structure capable of effectively releasing or relieving interface thermal stress in the thermal cycle process while ensuring good electrical connection and chemical stability is provided so as to break through the limitation of the traditional rigid integrated design on the long-term service performance of the device. Disclosure of Invention The invention aims to solve the technical problems that the performance of the traditional medium-temperature high-temperature electric device is attenuated and the structure is invalid due to the accumulation of thermal stress of an interface in the long-term thermal cycle service process, and the invention provides a high-reliability thermoelectric device introduced with a foam connecting layer and a preparation method thereof in order to overcome the defects of the prior art. A first aspect of the present invention provides a method of manufacturing a high reliability thermoelectric device incorporating a foam connection laye