Thermoelectric device with optimized structure and size

Abstract

One unit of the thermoelectric device is composed of a pair of unit temperature difference galvanic couples, two temperature electrodes, a pair of galvanic couples which are connected through transition electrode plates, and two common heat exchange heat dissipation plates with different temperatures. Two galvanic couple arms of the thermoelectric couple are made of two semiconductor materials, namely an N-type galvanic couple arm and a P-type galvanic couple arm, and are connected by a metal galvanic couple transition electrode plate at a cold or hot end temperature joint with the temperature of T0 or T1; the T0 transition electrode plate is combined with the heat exchange cold or hot end heat dissipation plate to form a T0 end heat exchange chamber; two arms of the N-type and P-type galvanic couples at the T1 temperature end are respectively connected with the metal electrodes and are electrode ends of the output of the thermoelectric device; the heat exchange radiating plate is a high-heat-conductivity insulating plate, and the cross sections of the N-type galvanic couple arm and the P-type galvanic couple arm are elliptical; multiple units are connected in series to form a thermoelectric device.

Description

Technical Field

[0001] The present invention relates to a thermoelectric device, and in particular to the optimization of the structure and size of the thermoelectric device. Background Art

[0002] From the 1820s to the 1840s, the three thermoelectric effects—the Seebeck effect (current flow due to temperature differences between conductors), the Peltier effect (temperature differences between conductors), and the Thomson effect (theoretical basis: the phenomenon of heat absorption and heat release when current passes through a temperature gradient field on a metal, i.e., the thermal effect of current)—were key discoveries in 19th-century physics. In the 20th century, the discovery of the thermoelectric properties of semiconductor thermoelectric materials advanced the application and development of the thermoelectric effect. In the 1950s, semiconductor physicist A.F. I.O.F.E.F. and his team developed semiconductor thermoelectric devices (hereinafter referred to as thermoelectric devices) and their underlying theory.

[0003] The three aforementioned thermoelectric effects, the basic theory of thermoelectrics, thermoelectric devices, and thermoelectric materials are the three pillars of thermoelectric application development. Thermoelectric applications encompass two main areas: 1. Thermoelectric devices convert thermal energy to electrical energy in a temperature differential thermal energy state, i.e., thermal power sources (also known as thermal power generation) and related thermal power generation applications; 2. Thermoelectric devices convert electrical energy to thermal energy (cooling and heating) in an external power supply state, i.e., electric cooling and electric heating products and their applications. Thermoelectric device applications have attracted the attention of users and specialized industries due to their unique environmental performance and longevity. They are ideal environmentally friendly power sources and are irreplaceable in certain specialized industries. Ecological temperature generally refers to temperatures ranging from -20°C to 200°C. Natural heat sources are abundant, and industrial and natural thermal energy reserves are substantial. Furthermore, a significant amount of wasted ecological heat is urgently in need of recovery. Therefore, the application of thermoelectric devices has enormous market potential and far-reaching prospects, and their environmental significance is also significant.

[0004] The key performance indicators for thermoelectric applications are thermoelectric conversion efficiency and electrothermal energy efficiency ratio (EER). Currently, thermoelectric device structures and their theoretical basis are being developed and applied. While thermoelectric devices offer advantages such as simplicity, reliability, and low cost, they suffer from low thermoelectric conversion efficiency and EER, particularly under ambient temperature conditions. The current state of application and development of thermal power sources and power generation equipment is not optimistic. Applications such as thermal power generation are costly and lack market competitiveness, presenting a bottleneck in the development of semiconductor thermoelectric devices. However, the semiconductor and computing industries offer a wealth of proven technologies, which have advanced the development of thermoelectric technology and products.

[0005] CN201510051468.8 discloses a bismuth telluride material with excellent thermoelectric performance in the medium temperature range and its preparation method. The bismuth telluride material has the general formula CuxBi0.3Sb1.7-xTe3, where 0.005≤x≤0.02. The bismuth telluride material in this invention effectively increases the material's carrier concentration through self-doping and Cu doping, significantly optimizing the material's electrical properties while suppressing intrinsic excitation. CN200310109130.0 discloses Bi2Te3-based nanocomposite thermoelectric materials. Bi2Te3-based nanostructured powders have a unique microstructure that produces unique physical and chemical properties, resulting in materials with exceptional carrier transport characteristics. This significantly improves the thermoelectric potential coefficient or electrical conductivity of the thermoelectric material, thereby increasing the material's thermoelectric power factor. Bi2Te3-based composites have also been synthesized using silver, antimony, and tin-doped bismuth telluride nanoparticles and bulk bismuth telluride to form N-type and P-type SKDs.

[0006] US patent application US13398274 discloses a rational design of a high-efficiency segmented TE power generation module by establishing a three-dimensional, fully parametric finite element model that couples thermoelectric effects (conduction, Joule, Thomson, and Peltier effects) and comprehensively considers temperature-dependent material properties. This model utilizes a filled galena material as the high-temperature segment, which is bonded to a bismuth telluride-based alloy for the low-temperature segment. Experimental results show good agreement with predicted results, taking into account electrical contact resistivity, interfacial heat transfer coefficient, bonding materials, and gap fillers. The module achieves a high efficiency of 12.0% at a temperature difference of 541°C. Importantly, by combining a rational structural design with developed bonding and fabrication techniques, the measured efficiency reaches 96.9% of the theoretical efficiency, based on the properties of the TE material itself. Undoubtedly, even higher power generation performance can be achieved in the future by using compatible TE materials with higher ZT. This work demonstrates a reliable path and guideline for achieving high conversion efficiency through segmented TE modules, which will accelerate the development of high-efficiency TE generators for a wide range of industrial applications in the near future. Module Manufacturing N-type and P-type SKD powders were prepared according to existing processes. Then, the TE segment of SKD with Ti-Al barrier layer and Ni contact layer was consolidated using a one-step hot pressing technique. N-type SKD and P-type SKD were sintered at 680℃ and 650℃, respectively, under a pressure of 60MPa for 1.5 hours. After grinding, polishing and cutting the sintered green compacts, the Mo 50 Cu 50Electrodes were bridged by brazing Ag-Cu-Zn alloy to form SKD elements. Glass fiber (HTI1100, Promaglaf) was then filled into the TE gap to minimize heat loss through convection and radiation. Copper wires were soldered to the cold-side copper electrodes for current and voltage measurement. Prior to high-temperature testing, the module was electrically tested at room temperature to ensure good interfacial bonding and integrity.

[0007] CN202210558584.9 discloses a test device for thermoelectric devices. Cai Wei and others have achieved a key breakthrough in the intelligent design of thermoelectric interface materials and the development of efficient devices, achieving a 9.25% thermal-to-electrical energy conversion efficiency at a 300K temperature gradient (science). The device utilizes a wide range of alloys or compounds as potential interface materials.

[0008] Zhang Qihao et al., Thermoelectric Power Generation Devices and Application Technologies: Current Status, Challenges, and Prospects, Journal of Inorganic Materials, March 2019, published the following: Although the discovery of thermoelectric materials bismuth telluride, lead telluride, and silicon-germanium alloys has enabled the commercial application of devices, and the record of ZT, a landmark indicator of thermoelectric material performance (dimensionless thermoelectric figure of merit), has exceeded 1.5 or even 2.0; it provides a material basis for the leap in thermoelectric conversion technology, but thermoelectric device technology still needs to develop, and the application of devices in waste heat power generation applications such as steel, chemical industry, and power generation is still limited.

[0009] The π-type element (flat-plate device) is the most typical thermoelectric device. The conversion efficiency of most thermoelectric devices is below 10%. The SiGe and PbTe-based thermoelectric devices used in US spacecraft have an efficiency of 7-7.6%, while the efficiency of commercial Bi2Te3-based thermoelectric devices is between 4-7%. For example, the commercial device 71 has a conversion efficiency of 6.0% for bismuth telluride at a temperature difference of 217K. The current measured efficiency of devices is still far lower than the theoretical value calculated from the material's ZT. The Japanese Furukawa single-pole CoSb3 has a conversion efficiency of 8% at a temperature difference of 550K. The existing theory explains that the heat Qh at the high-temperature end of the device is converted into four parts of heat: conduction heat Qc, Peltier heat Qp, and Joule heat Qj. The theoretical thermoelectric conversion efficiency η is as follows, where P is the output power at the load.

[0010] Device design methods have been made public, such as energy balance models, one-dimensional or three-dimensional heat conduction models, equivalent circuit models, etc. Interface contact optimization and thermoelectric device integration technology are also developing.

[0011] The thermoelectric device structure developed based on the Joffe theory is one of the excellent thermoelectric products, but the device preparation and performance cannot be equated with the thermoelectric effect. The device operates in a mixed thermal and electrical environment, ignoring the perfect environment in the Joffe basic theory, especially the theoretical research and understanding of the environment in which the thermoelectric device operates. It will be ignored in the actual design and calculation of thermoelectric devices.

[0012] Experimental analysis of thermoelectric device operation and the results indicate that the current Yoffe device structure, based on the current performance of thermoelectric materials, can improve thermoelectric conversion efficiency and energy efficiency. Effective measures can also be taken to improve the functional performance of thermoelectric devices. While developing thermoelectric materials to improve intrinsic performance, it is not the only viable technological approach. Improvements in device design could advance the development of Yoffe thermoelectric products.

[0013] Performance indicators such as "conversion efficiency" and "conversion coefficient" of Yophi thermoelectric devices (hereinafter referred to as devices) are no longer sufficient to meet demand. A thorough understanding of Yophi's classical calculations and device structure also hinders the device's performance in practical applications. This invention, based on the following four documents, can improve and promote technological innovation in thermoelectric devices, enhance their performance, and promote the development of thermoelectric applications.

[0014] 【1】Russian А·Ф·ИОФФЕ《ЦИЗИКΑПОЛУПРОВДНИКОВ》МОСКВАЛЕНИНГРЛД1956p382-393;

[0015] 【2】UK AFIOFFE "semiconductor thermoelements and thermoelectriccooling"

[0016] INFOSEAHCH LIMITED L.QNDON 1957;

[0017] 【3】Huang Kun and Xie Xide, Semiconductor Physics, Science Press, 1958, pp. 145-165;

[0018] 【4】Zhong Guangxue et al., Semiconductor Refrigeration Devices and Their Applications, Science Press, 1992

[0019] 【5】Chen Lidong, Thermoelectric Materials and Devices, Science Press, November 2018.

[0020] Reference [1] is the original Russian version of Joffe's work, a universally recognized document on the fundamental theory of semiconductor physics. [2] Joffe's English professional edition of the thermoelectric device document is an important document for the dissemination of thermoelectric theory in Europe and the United States. Reference [3] is the earliest Chinese translation of reference [1]. It was published in 1958 as the first edition in the semiconductor field in China and had been printed seven times by 2012. Reference [4] is derived from the Chinese translation of the English version of [2]. Joffe's thermoelectric theory has a great influence. However, there is no complete derivation formula for the heating calculation of thermoelectric devices in China, similar to the derivation formula for the cooling of thermoelectric devices.

[0021] With the deepening of research on thermoelectric effect and the expansion and widespread development and application of thermoelectric devices, Ioffe's original version of the basic theory of thermoelectricity is still worthy of attention, that is, the original documents [1] and [2] are still very important.

[0022] The terms and symbols used in this application are as follows: The meaning of commonly used symbols: Conversion of heat to electricity (R→D) Conversion of electricity to heat (D→R) D is electricity, R is heat, G is the high temperature end T1, L is the low temperature end T O , temperature unit: K, temperature scale, ε potential, ε P Peltier potential, ε S Seebeck potential, ε T Thomson potential, V r =Ir device internal resistance r voltage drop, V R Voltage drop under load R; V is voltage unit, volt; I is current unit, ampere; N is power watt W; thermal energy and electrical energy unit is joule.

[0023] Z: material merit 1 / K, ZT: material merit coefficient M: material merit (composite coefficient).

[0024] k: thermal conductivity in mW / cm˙K, α: material thermoelectric coefficient in V / K, η: efficiency (%); energy efficiency coefficient: η R R→D Conversion efficiency, η D D→R Conversion efficiency coefficient Δ=T1-T0 temperature difference, ∫ integral symbol Partial differential symbol d differential symbol.

[0025] Figure 1 This is a schematic diagram of a unit structure of a thermoelectric device disclosed in the prior art, and its basic structure is the same as that of the present invention. The device consists of a pair of unit thermocouples, two temperature electrodes, a thermocouple transition electrode, and two common heat exchange heat sinks with different temperatures. The thermocouple's thermocouple arms are composed of two types of semiconductor materials, N-type (thermocouple arms) and P-type (thermocouple arms r1, r2). At the cold temperature joint with a temperature of T0, they are connected with a metal thermocouple transition electrode, and the transition electrode plate 3-3 with a temperature of T0. Figure 2 As shown, the transition electrode plate 3-3 of T0 is combined with the heat exchange cold end heat sink 1-1 to form the heat exchange chamber at the T0 end. The heat exchange heat sink is made of high thermal conductivity and high insulation material.

[0026] At the hot end with a temperature of T1, the two arms of the N-type and P-type electric couple are connected to the metal electrodes 3-1 and 3-2 respectively, which are the electrode ends of the thermoelectric device output. The outer sides of the two electrodes (plates) are combined with the heat sink 1-2, as shown in the figure. Figure 2 Lower side ( Figure 1 The side view (upside down) shows the T1 side of the device. The heat sink requirements for the T1 side are the same as those for the T0 side.

[0027] Two electrode plates receive electrical energy from a thermocouple. When the electrodes receive external electrical energy, the thermoelectric device converts electrical energy into thermal energy. When electrical energy is input or the polarity of the input is changed, a temperature difference forms between the cold and hot ends, and the temperature difference between the cold and hot ends also changes, which is the cooling and heating phenomenon of the device. The cooling and heating principles of thermoelectric devices can be changed by the polarity of the input power supply. This is the basic operating principle of thermoelectric devices.

[0028] The following introduces the principles and methods of improving the performance of thermoelectric devices. Based on the three thermoelectric effects and the working principle of the Yoffian thermoelectric device, Figure 1 In the above example, let ε S represents the thermoelectromotive force rate of the thermocouple, Peltier electromotive force ratio. ρ1 and ρ2 represent the resistivity of the two arms, S1 and S2 are the cross-sections of the two electric dipole arms, L represents the arm length, let r1 and r2 represent the resistance of the two arms respectively, k1 and k2 are the thermal conductivity of the two arms, then the resistance of the loop (in series) and the thermal conductivity between the hot and cold ends (in parallel) are

[0029]

[0030]

[0031] When current passes through the thermal junction, the Peltier heat absorbed per unit time is

[0032]

[0033] At the same time, the heat released by the cold joint

[0034] Q0=-∫ε PT0 I (4)

[0035] Due to heat conduction, the amount of heat transferred from the hot joint to the cold joint is

[0036] Q T =K(T1-T0). (5)

[0037] The working performance of thermoelectric devices is directly related to the thermal conductivity k of the thermoelectric material and the internal resistance r of the thermoelectric device (related to ρ1 and ρ2): Equations (1) and (2).

[0038] The correlation equations (3), (4), and (5) are the figure of merit Z of thermoelectric materials.

[0039] Therefore, to obtain high performance in thermoelectric devices, the kr value must be reduced.

[0040] The maximum energy conversion efficiency η of a thermoelectric device is determined by the following formula:

[0041]

[0042] Among them, Th and Tc are the device's operating hot and cold end temperatures, respectively, and ZTave is the average ZT figure of merit within the operating temperature range. The above ZT is a dimensionless value that measures the characteristics of thermoelectric materials. ZT = S2σT / κ, which is only related to the material's intrinsic physical properties, Seebeck coefficient (S), electrical conductivity (σ) and thermal conductivity (k). It is not difficult to see that the temperature difference during the operation of the thermoelectric material and the ZTave value of the thermoelectric material are the key to determining the conversion efficiency of the thermoelectric device. However, the above parameters related to ZT in the thermoelectric material are mutually coupled, which makes it impossible to increase the ZT value of the thermoelectric material indefinitely.

[0043] The above-mentioned thermoelectric devices are the mainstream thermoelectric devices in the current market (hereinafter referred to as "devices"). References [1], [2] and [3] are the theoretical basis for the practice of devices. The references use the main parameters R and r of thermoelectric materials to analyze the influence of the mutual conversion efficiency of thermal energy power and electrical energy (power) in thermoelectric devices, and derive the principle of improving device performance.

[0044] Material parameters k and r are the result of the generalized spatiotemporal influences shared by spacetime and time. They are affected not only by changes in the dimensions of three-dimensional space but also by time t. They are also functions of temperature and temperature difference. When applying thermoelectric devices, we typically only consider the effects of heat on k and r. Essentially, this is the process of converting thermal energy into electrical energy, generated by the influence of the device material's (intrinsic) properties under spatial and temporal fields, while ignoring the changes in the material properties of the spatial field caused by the temporal field. While improving the efficiency of existing devices requires improvements and progress in intrinsic material properties, interfaces, and the influence of spatial and temporal fields, changes in the dimensions of three-dimensional space still have positive, even revolutionary, significance. Summary of the Invention

[0045] The present invention aims to improve the device's performance parameter η (conversion efficiency) by optimizing its structural shape and dimensions, through changes and modifications in the device structure and three-dimensional dimensions, and to obtain experimental support. The present invention's device optimization is based on a thorough understanding and development of the Yoffi semiconductor thermoelectric device and its underlying theory, building on the current strengths and weaknesses of thermoelectric devices. Given that the three thermoelectric effects remain the foundation of the underlying theory of Yoffi devices and their applications, while respecting the Yoffi devices and their theoretical achievements, further analysis and exploration of areas not yet understood are needed. Difficulties in thermoelectric device development are identified, and the underlying theory of Yoffi thermoelectric devices and their applications is refined and further developed. To this end, the present invention proposes optimizing the structure, component shapes, and dimensions of Yoffi thermoelectric devices, significantly improving their performance.

[0046] The technical solution of the present invention is a thermoelectric device, wherein one unit of the thermoelectric device is a pair of unit thermocouples, two temperature electrodes 3-1 and 3-2, a pair of thermocouples connected by a transition electrode 3.3, and two common heat exchange heat sinks at different temperatures. The thermocouple's two arms are composed of two semiconductor materials, an N-type thermocouple arm and a P-type thermocouple arm. At the cold (or hot) temperature junction at temperature T0 or T1, the two thermocouple arms are connected by a metal thermocouple transition electrode plate 3-3. The T0 transition electrode plate 3-3 is combined with the heat exchange cold (or hot) end heat sink 1-1 to form the T0 end heat exchange chamber. The temperature end is T1 (often referred to as the hot end), where the N-type and P-type thermocouple arms are connected to the metal electrodes 3-1 and 3-2, respectively, and serve as the output electrode end of the thermoelectric device. The heat exchange heat sink is a high heat transfer and insulating plate, and the N-type and P-type thermocouple arms have elliptical (circular) cross-sections. Multiple units are connected in series to form the thermoelectric device.

[0047] Furthermore, the cross-sectional area of the N-type electric dipole arm or the P-type electric dipole arm changes, and the basis for the change is the thermoelectric material performance ρ n ≠ρ p , ρ n >ρ p , so the area S of N-type electric dipole arm or P-type electric dipole arm is used n To regulate r n 、r p To ensure r n =r p , when r n =r p Can obtain the current I in the two arms of the electric couple n =I p Set the cross-sectional area of the N electric dipole arm to be larger than the cross-sectional area of the P electric dipole arm.

[0048] The cross-sectional area of the N electric couple arm is 3-17% greater than the cross-sectional area of the P electric couple arm.

[0049] The cross-sectional area of the N electric dipole arm is 13±3% greater than the cross-sectional area of the P electric dipole arm. The increase in the cross-sectional area of the N electric dipole arm increases the material figure of merit Z of the thermoelectric device by 17±5%, thereby improving the conversion efficiency of the thermoelectric device.

[0050] The electric couple arm in the thermoelectric device is cylindrical.

[0051] The arcs at both ends of the "transition connecting plate" of the electric couple arm in the thermoelectric device are also connected by arcs or obtuse angles.

[0052] The edges and corners of all electric couple arms and joints in the thickness direction are optimized to be arcs or obtuse angles.

[0053] The two electric dipole arms of each unit are arranged so that the currents in the dipoles are in opposite directions; the currents in the electric dipole arms of adjacent units are also in opposite directions, so as to minimize the interference of the adjacent inductive magnetic field on the current carried in the dipoles.

[0054] Optimization of the shape of structural components: The current Yoffe thermoelectric device is a product made based on the three thermoelectric effects and the Yoffe thermoelectric theory. Its structure not only follows the three thermoelectric effects, but also follows the basic rules of distribution of charge, electric potential, etc. in thermal and electrophysics. The electric potential, etc. strive to be uniform, and the distribution curvature radius is the largest. According to Yoffe's thermoelectric device theory, the actual production has not yet followed the Yoffe theory. The unit component that constitutes the device is a thermocouple, and the two arms of the unit's thermocouple are columns with a square area. According to the theory of electrical engineering, the charge is evenly distributed in the circular area to obtain the best effect. That is to say, the circular (including elliptical) area is the best preferred shape of the component. That is, the shape of the thermocouple arm in the device unit is preferably a circular (including elliptical) cylinder, see Figure 2 Whether the structure and shape of components are reasonable or not affects the performance of thermoelectric devices. The answer is clear and will be discussed in detail in the following optimized implementation schemes and technologies.

[0055] The electric couple arm in the thermoelectric device is optimized to be cylindrical to achieve the best electrical performance. Figure 3 , optimize the "transition connecting plate" of the electric couple arm in the thermoelectric device to Figure 3 c. The arcs at both ends of the transition plate (also known as the transition electrode plate) are also connected by arc-shaped matching. The thickness-direction corners of the transition plate (including all dipole arms, connectors, etc.) are also optimized to arcs (rather than right angles) or obtuse angles during processing to reduce charge concentration. Optimizing corners is also a component of device optimization, reducing charge concentration and the skin effect, which improves the performance of thermoelectric devices.

[0056] The present invention involves theoretical disciplines related to thermodynamics, electricity, and electromagnetism within the discipline of physics. Understanding, learning, and mastering the theoretical foundations and scientific research achievements provided by predecessors are the foundation of the present invention. The theory of thermoelectric devices and thermoelectric applications belongs to the discipline of physics.

[0057] From an operational analysis, the structure of a thermoelectric device is an electromagnetic structure product. When current passes through the thermocouple element, an electromagnetic field is formed, which satisfies the space described by Maxwell's equations. Some scholars have focused on the effect of electromagnetic fields on the operation of carriers in thermocouples. The present invention proposes device optimization content, and all the edges and corners of the electric dipole arms and joints in the thickness direction are optimized to be arc-shaped and blunt-angled. The present invention proposes: in the device structure, the two electric dipole arms of each unit are arranged so that the current directions in the electric dipoles are opposite; the currents in the "transition connection plates" of the electric dipole arms of adjacent units should also be opposite. At the same time, there should be a reasonable distance between the N-type electric dipole arm and the P-type electric dipole arm and the electric dipole arms between adjacent units, so as to minimize the electromagnetic interference of the adjacent inductive magnetic field on the carriers in the electric dipole.

[0058] This invention also includes the basis for optimizing the structure of the Yoffie thermoelectric device, along with theories related to specialized physics disciplines such as thermal and electrical engineering, and analyzes optimization methods. Based on experimental results and theories related to related disciplines, innovative optimization of existing thermoelectric device components is performed, and the performance and improved effects of the optimized thermoelectric device are analyzed and verified.

[0059] In thermoelectric devices, thermal energy is distributed in three dimensions, while after thermal energy conversion, electrical energy is transported in one dimension. Therefore, the mutual conversion of thermal energy and electrical energy in thermoelectric devices, and the fundamental theories of thermodynamics and electricity in physics, also underlie the theory of thermoelectric devices and their applications. Some aspects of Joffe's theory of thermoelectric devices remain unappreciated or unaccepted (sometimes due to typos or misunderstandings in Joffe's original publication). Regarding the electrical work done by thermoelectric devices, and the energy conversion between thermal energy and electrical energy (work), Joffe's discussion of thermoelectric device efficiency uses the ratio of thermal energy power to electrical energy (power) through heat conduction, failing to describe or directly avoiding the ratio of energy (work) related to time and space.

[0060] Thermoelectric material merit, Z (also expressed as ZT and M), describes the ratio of thermal power to electrical power. Here, k is the thermal conductivity and r is the internal resistance of the device. Therefore, merit, Z = kr, directly affects the efficiency of the conversion. In thermal energy transfer, k is the material's thermal conductivity index in units of mW / cm˙K, which is directly related to power, length, and temperature difference. And r is the device's resistance. In thermoelectric devices, the basic unit structure of the device is as follows: Figure 1 As shown in the figure, the basic unit is a pair of thermocouples. That is, the thermoelectric device unit is a thermocouple whose arms are made of two semiconductor materials, P and N.

[0061] The unit's kr is a direct indicator of device performance. Therefore, thermoelectric devices involve two physical disciplines: thermal and electrical. Devices must adhere to the fundamental principles of both thermal and electrical engineering.

[0062] The cross-sectional area of the N electric dipole arm is set to be lower than that of the P electric dipole arm. This is based on theory and practice. The resistivity of the N electric dipole arm (N-type thermoelectric material) is higher than that of the P electric dipole arm. From the mechanism of electric field and electrothermal balance, the cross-sectional area of the N electric dipole arm is 3-17% higher than that of the P electric dipole arm, especially 13±3%.

[0063] The two semiconductor materials of the N-type electric dipole arm and the P-type electric dipole arm can adopt existing solutions.

[0064] Two electrode plates receive electrical energy from a thermocouple. When the electrodes receive external electrical energy, the thermoelectric device converts electrical energy into thermal energy. When electrical energy is input or the polarity of the input is changed, a temperature difference forms between the cold and hot ends, and the temperature difference between the cold and hot ends also changes, which is the cooling and heating phenomenon of the device. The cooling and heating principles of thermoelectric devices can be changed by the polarity of the input power supply.

[0065] N-type thermoelectric materials are based on PbTe and SiGe. The ZT value of N-type PbTe-based materials is not high within the operating temperature range.

[0066] The optimization content and method of the thermoelectric device of the present invention is based on the development of the thermoelectric device theory and the professional disciplines of thermal and electrical engineering, and makes three aspects of optimization. First, the shape of the current thermoelectric device components is optimized; second, the size of individual components (including connecting components) in the thermoelectric device (unit) is optimized; third, the arrangement and distribution of the thermoelectric device units are reasonably optimized. Figure 1 As shown, in the unit couple, the two arms form a current that flows in opposite directions, just as the electromagnetic field described by Maxwell's equations, the thermoelectric device operating in the electromagnetic field is affected.

[0067] This invention proposes that the shape and arrangement of thermocouples (and their connectors), as well as the distance between adjacent thermocouples and the resulting self-coupling of thermocouples, are the primary factors affecting their performance. This approach optimizes the performance of existing thermoelectric devices. All corners along the thickness of the thermocouple arms and connectors are optimized to be curved and blunt.

[0068] The two electric dipole arms of each unit in the device are arranged so that the currents in the dipoles are in opposite directions; the currents in the "transition connection plates" of the electric dipole arms of adjacent units should also be opposite. At the same time, there should be a reasonable distance between the electric dipole arms to minimize the electromagnetic interference of the adjacent inductive magnetic fields on the carriers in the electric dipoles.

[0069] Beneficial Effects: Based on currently produced Yoffe thermoelectric devices, the present invention optimizes the device structure and size, exploring the performance potential of Yoffe thermoelectric devices. The present invention can fully improve the efficiency of Yoffe thermoelectric devices. Even when the cross-sections of the N-type and P-type electric dipole arms are circular or elliptical, the efficiency can be improved by 3%. The present invention is a refinement of the Yoffe theory and an innovation in the application of devices. Combined with the changes in the cross-sections of the N-type and P-type electric dipole arms, the efficiency of the thermoelectric device unit of the present invention is increased by 7-15% (the increase in the Z value is greater than this). That is, after the modification of the original device by the present invention, the efficiency of the cylindrical electric dipole arm with the same power and the same cross-sectional area is improved by more than 10% compared to the efficiency of the square pole with the same cross-sectional area, increasing the efficiency of the existing thermoelectric device from 7% to more than 8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1This is a schematic diagram of a unit structure of a thermoelectric device. The structure of the N-type electric couple arm and the P-type electric couple arm of the present invention with an elliptical (circular) cylindrical cross-section is the same as this structure.

[0071] Figure 2 Shown Figure 1 side view.

[0072] Figure 3 a. Figure 3 b are cross-sectional views of the N-type electric dipole arm and the P-type electric dipole arm in the thermoelectric device (the prior art and the present invention have different cross-sectional views, see the following statement), Figure 3 c. The shape of the "transition connecting plate" of the electric couple arm;

[0073] Figure 4 4a and 4b respectively represent the curves of metal resistivity and semiconductor resistivity versus operating temperature.

[0074] Figure 5 5a and 5b are the curves of the temperature difference electric couple of N and P type semiconductor thermoelectric materials and the curves of the resistivity of the two electric couple arm materials changing with temperature respectively.

[0075] Figure 6 a is the optimized electrode arm. a is the schematic diagram of the connection between the electrode and the electrode;

[0076] Figure 6 b is a schematic diagram of the electric dipole arm electrode (transition electrode plate);

[0077] Figure 6 c is the unit galvanic distribution size, which is selected based on the typical parameters of mainstream products and anti-interference requirements.

[0078] Figure 7 a. Figure 7 b is a schematic diagram of the device unit connection. DETAILED DESCRIPTION

[0079] The invention discloses a structure of a thermoelectric device and a principle for optimizing the size of structural components and introduces a method and a process for implementing the same.

[0080] The current unit structure dimensions of thermoelectric devices are as follows: the existing N-type electric couple arm and P-type electric couple unit column are 4x4x4 mmS1=16; if T0 is the cold end, at the cold end temperature joint with temperature T0, a metal transition electrode is connected, and the transition electrode plate 3-3 with temperature T0 is combined with the cold end heat exchange cold end heat sink 1-1 of T0 to form the heat exchange chamber at the T0 end; similarly, the hot end heat exchange heat sink of T1 is combined with the electrode plate to form the heat exchange chamber at the T1 end. The heat exchange heat sink is a high thermal conductivity and insulating plate. It is generally believed that ρ n >ρ p 5-6%;

[0081] The cross sections of the N-type electric couple arm and the P-type electric couple arm of the present invention are circular.

[0082] The resistivity of semiconductors is different from that of metals. Figure 3 As shown. The resistivity of different N-type and P-type semiconductor materials is also different, see Figure 5 , document [5] p132, and the cited article. To ensure the current and voltage balance of the electric dipole arms, the cross-sectional areas of the electric dipole arms should be different. This is the theoretical basis of the present invention. Yofei is used to find the extreme value of the figure of merit Z. It is the guarantee for optimizing the structure and improving performance.

[0083] in accordance with Figure 5 The resistivity of the material and the further design of the cross-sectional area of the electric dipole arm are important aspects of technical optimization. Setting a reasonable cross-sectional area of the P electric dipole arm can optimize device performance.

[0084] The "transition connecting plate" of the thermoelectric device's electric couple arm is optimized accordingly. The arcs at both ends are also connected using matching arcs. This not only improves performance, but also saves materials and simplifies the process. This invention's innovative optimization environment is based on the disciplines of thermodynamics and electrical engineering.

[0085] Figure 1 This is a diagram of the unit structure of a current (mainstream) thermoelectric device. 2-1 and 2-2 are thermocouple units. N is the semiconductor N-type electron carrier arm 2-1, and P is the P-type hole carrier arm 2-2. 3-1, 3-2, and 3-3 are all electrodes (of the thermocouple arms), made of conductive metal. 3-1 and 3-2 are also unit (device) electrodes, and 3-3 is the connecting electrode for the thermocouple unit, also serving as the connecting electrode for the thermocouple unit. 1-1 and 1-2 are heat sinks (heat conduction plates), made of highly thermally conductive ceramic alumina plates and also electrically insulating materials. 1-1 and 1-2 are connected to the high- and low-temperature ends of the thermocouple arms, respectively, forming the high- and low-temperature heat exchange chambers. The outer (outer) sides of the 1-1 and 1-2 plates are fused to the ambient temperature, forming heat exchange chambers T1 and T0 with the ambient temperature.

[0086] Figure 1 The device in the middle is connected to the external load R, which is the equivalent diagram of the power generation function of the thermoelectric device.

[0087] Figure 3 a is a schematic diagram of the current device structure (mainstream products) electric dipole arm carrying area. Figure 3 The electric dipole arm in a is a square column, which represents the prior art. The circle (solid line) in the figure is the inscribed or circumscribed circle of the square cross-sectional area, which is used in the present invention.

[0088] That is, the electric couple arms in the existing thermoelectric devices are square column-shaped, while the present invention adopts electric couple arms with a cylindrical structure having a larger diameter, especially N-structure electric couple arms. Figure 3 The dashed line b is the radius of the circle representing the equivalent cross-sectional area of the current distribution (equal to the cross-sectional area of the square). An increase in the Z value directly affects M, the comprehensive figure of merit derived by Joffe. M and the temperature difference ratio directly affect efficiency. Efficiency calculation formulas are currently inconsistent. Increasing the Z value increases efficiency. Efficiency calculations have been expressed in linear, √, and even square terms. The present invention adopts a conventional expression.

[0089] According to the existing 2~6mm 2 The cross-sectional area of the electric dipole arm can increase the material merit Z of the device by 17%.

[0090] Circle 3c is the transition electrode plate connecting the two electric dipole arms.

[0091] Figure 3 b is also a schematic diagram of the optimized electric dipole arm shape.

[0092] Figure 4 Curves of semiconductor resistivity, metal resistivity and operating temperature.

[0093] Figure 5 It is a curve showing the change of temperature of thermocouples made of two types of semiconductor thermoelectric materials, N and P, and the change of resistivity of two thermocouple arm materials with temperature. Different thermocouple arms have characteristics that affect the function of thermoelectric devices due to the difference in temperature potential and resistivity.

[0094] Figure 6 -a is the optimized electrode arm. It is the schematic diagram of the connection between the electrode and the electrode.

[0095] Figure 6 -b is a schematic diagram of the electric dipole arm electrode (transition electrode plate); the electrode plate is connected to the two electric dipole arms as shown in Figure 6 -a;

[0096] When the electrode plate is the output electrode, one end of the transition electrode plate is connected to the output line, and the other end is connected to the electric couple. When the N-type electric couple arm is connected to the Rn wire disk, when the P-type electric couple arm is connected to the Rp phase, the other end is the output electrode.

[0097] The transition connection plate has Rn and Rp discs which are PCB soldering pads of the Rn and Rp electric couple arms respectively.

[0098] In fact, the galvanic electrode and the transition electrode are the same PCB metal electrodes (PCB is a printed circuit board method for circuit connection). Ensure that the PCB structure of the unit galvanic electrode connection is efficient and reasonable in the device chip structure.

[0099] Figure 6 -c is the unit galvanic distribution size, which should be selected based on the typical parameters of mainstream products and anti-interference requirements. The unit distribution should also comply with this.

[0100] Figure 7 a. Figure 7 b is a schematic diagram of the device unit connection. The device electrode output terminal should be suitable for the product use environment. It can be on one side, in the middle, or on both sides. Figure 7 a in the middle of one side and on both sides of one side ( Figure 7 b); The connection between the unit electric dipole arm and the electric dipole arm transition plate and the unit electric dipole should comply with the electromagnetic field anti-interference arrangement rules, which include two aspects: (1) the unit electric dipole, and (2) the arrangement of the electric dipole unit. The currents of the two electric dipoles of the unit are opposite. In the arrangement of the electric dipole unit, it is necessary to ensure that the currents and flows in the adjacent electric dipole arms are opposite to each other, so as to offset the magnetic field of the adjacent electric dipole arms, reduce the influence of the magnetic field on the interceptor, that is, reduce the influence on the thermoelectric potential (Seebeck potential) and the Peltier potential. Similarly, the current in the transition electric dipole arm connection plate in the ⊥ direction of the electric dipole and the current in the adjacent transition electrode should also comply with the arrangement rules to ensure the offset of the adjacent magnetic field and reduce interference with the carriers. Figure 7 a and 7b are two of them, and the arrangement can be selected according to the number of units in the device.

[0101] The thermoelectric device unit is composed of two semiconductor materials, P and N, in the form of a couplet. Undoubtedly, the couple kr of the unit directly represents the performance of the device. Therefore, thermoelectric devices involve two physical disciplines in nature, thermal and electrical. For the two couplet arms of the device, the thermal conductivity k is affected not only by the length of the couplet arms, but also by the cross-sectional area of the couplet arms and the temperature difference between the two ends of the arms. The resistivity ρ is more affected by electricity than by thermal factors, and its influencing factors are more numerous in the electrical range. In the electrical range, the resistivity is also affected by the material types N and P of the couplet arms, that is, ρ n ≠ρ p In the electrical environment, there is also the influence of cross-sectional shape on ρ, such as Figure 3 In a, ρ is usually different from its metal counterpart. The resistivity increases with the increase of the temperature of the electric dipole arm environment, and the resistivity increases with the decrease of temperature. The resistivity of the semiconductor becomes as follows: Figure 3 b (In a certain range, the resistivity will increase with decreasing temperature, and will turn from decreasing to increasing. When the thermoelectric device is operated in the selected ecological environment, under this temperature range, its resistivity will decrease and then increase. Different types of semiconductor materials and semiconductor resistivity are not necessarily the same.) Please refer to Figure 3 c.

[0102] In the context of electrical science, when the cross-sectional area is the same, the cross-sectional shape affects the size of the resistance, such as Figure 3 a and Figure 3b. There is a problem of effective resistance cross-sectional area and invalid cross-sectional area. In the field of electricity, the distribution of charge always strives to be uniform, and strives to be uniformly distributed with the smallest curvature radius. In the electric field excited by the circular cross-section according to the electrical principle, the electric field in the direction of the center of the circle can be perpendicular to the cross-section. For a square cross-section, the four corners of the charge distribution are uneven, and an invalid cross-sectional area will appear. Therefore, the current in the electric dipole arms of both n and P type materials is affected, that is, the electrical environment has strict requirements on the cross-sectional shape and size of the electric dipole arms; when the cross-sectional area is the same, the cross-sectional shape and its curvature radius are the same and as large as possible. If the temperature difference in the two electric arms is the same, the generated thermoelectric potential, that is, the Seebeck potential is equal, ε S =α(T1-T0) where α is the thermoelectric potential coefficient, T1 is the high temperature end temperature, and T0 is the low temperature end temperature.

[0103] Therefore, the current generated in the two electric dipole arms of the device unit is consistent. If the resistance of the two electric dipole arms is unequal, r n ≠r p When the current is unbalanced, there will be uneven Joule potential work, that is, Thomson power generated in the two arms. Actual thermoelectric devices should be perfected and processed according to the basic theoretical requirements of electricity and heat.

[0104] The current directions in the two arms of the thermocouple are exactly opposite, forming an electromagnetic field environment described by Maxwell's equations. Therefore, there is an electromagnetic field around the two arms of the thermocouple. Therefore, the distance of the electromagnetic field to the two arms of the thermocouple and the arrangement of the unit thermocouple arms will affect the efficiency of the thermoelectric device function.

[0105] 1. Content and methods of thermoelectric device optimization

[0106] Three aspects of optimization are being carried out. First, the shape of the current thermoelectric device components is optimized; second, the size of individual components in the device is optimized; and third, the arrangement and distribution of the device units are rationally optimized.

[0107] 1-1) The electric couple arm in the thermoelectric device is optimized to a cylindrical shape to achieve the best electrical performance. Figure 2 Optimize the "transition connection plate" of the electric couple arm in the thermoelectric device to Figure 2 The arcs at both ends of the transition plate are also connected by matching arcs. The corners of the thickness surface of the transition plate are also optimized to a small arc during processing to reduce charge concentration. Optimizing the corners on the component surface is also a component of device optimization, reducing charge concentration and the skin effect, which improves the performance of thermoelectric devices.

[0108] 1-2) Optimization of structural component size

[0109] The size of thermoelectric devices directly affects the performance of the device. The current of the device for power generation and thermoelectric cooling (heating) is carried by the electric dipole arm. The magnitude of the current is determined by the internal resistance of the device. Each unit component has a fixed resistance, and the number of units n is connected in series. The resistance of each unit r0 is the sum of the resistances of the two electric dipole arms r n 、r p By connecting in series, Figure 1 , r0=r n +r p , the total internal resistance r = nr0, n is the number of units in the device, and the size of r0 is determined by the resistivity ρ of the electric dipole arm N ,ρ P And the length L of the electric dipole arm and the cross-sectional area S of the electric dipole arm N ,S P , N, P are the N, P carrier characteristics of different electric dipole arms; where N is the electron carrier, P is the hole carrier, N, P are two semiconductor materials with different carrier characteristics. Due to the different material carriers, the resistivity ρ N ,ρ P The resistivity of semiconductor metal materials is different from that of metals. The resistivity ρ of metal materials decreases with temperature T(K), while the ρ of semiconductor metal materials increases after a certain temperature T. Figure 4 a and Figure 4 b.

[0110] Dipole arm resistance r n From the resistivity ρ N , cross-sectional area S N , the length L determines:

[0111] r n =ρ N L / S N , (1) Similarly,

[0112] r p =ρ P L / S P .(2)

[0113] From Figure (3), we know that because ρ N ≠ρ P , so r n ≠r p Because the two electric dipole arms are connected in series, the current flowing through them is the same.

[0114] If I N ≠I P The unequal current in the unit couple generates unequal temperature difference and voltage at both ends of the couple, which results in current imbalance and affects the performance of the device. Therefore, the cross-sectional area S of the two couple arms is kept constant under the same temperature difference and voltage. N ≠S PWhen the currents are not equal, rn=rp can be adjusted to make them consistent, so that the temperature difference between the two thermocouples remains unchanged, the voltage is the same, and the current is balanced.

[0115]

[0116] According to formula (3), ρ N S P =ρ P S N ρ N> ρ P Time S P >S N

[0117] Select the cross-sectional area S from this P >S N The cylindrical structure of ρ N , ρ P The performance remains unchanged. This is an optimization scheme by changing the cross-section of individual components of the device. Circular (elliptical) cylindrical structures with different cross-sectional areas result in different ρN and ρP, but the performance remains unchanged. This is an optimization scheme by changing the cross-section of individual components of the device. This optimization scheme does not change the performance of the thermoelectric device when the device is powered on. The optimization is r n With r p No change, reference Figure 3 When determining the appropriate circular cross-sectional area S P Replace square S p ; Sn and S p The optimization of the present invention can obtain the effect of excellent device improvement. It is an improvement of the Yoffe theory. Considering ρ N , ρ P The difference is due to the focus on the properties of different materials, which is also an important improvement of the present invention. Reference [5] p132, and the cited citations. Therefore, the present invention is based on the innovative optimization space generated by the thermoelectric device of Yoffie.

[0118] This optimization scheme does not change the performance of the thermoelectric device when the device is powered, and is optimized to r n With r p No change, reference Figure 3 a. Figure 3 b, when the circle area S is selected P Replace square S Z Time S P Z , due to the uniformity of electrical distribution, S Z The equivalent area is S P , that is, r p The performance remains unchanged, and the ineffective area when powered on is saved, thereby improving the heat conduction efficiency.

[0119] Because S​N P When r n =r p , which not only satisfies the current balance of the unit couple in the device, but also reduces S p area, while also improving heat conduction performance.

[0120] like Figure 1 As shown, in the unit couple, the two arms form a thermoelectric device in which the current flows in opposite directions, which is also worthy of attention.

[0121] The present invention proposes that the arrangement rules of unit thermocouples and the self-coupling of thermocouples adjacent to each other are the main factors affecting their performance, thereby optimizing the performance of current thermoelectric devices.

[0122] 2. Verification of the innovative optimization effect of thermoelectric devices by the present invention.

[0123] The conversion efficiency of thermoelectric devices in Joffe theory is the main performance indicator of thermoelectric devices.

[0124] The electrical efficiency of the thermoelectric device is

[0125] Where η RD It is the efficiency coefficient of converting thermal energy into electrical energy.

[0126] The foot code RD indicates the conversion of thermal energy into electrical energy.

[0127] η RD It is the ratio of the high-end temperature T1 to the low-end temperature T0 of the device under the temperature difference state

[0128] M is the comprehensive merit coefficient derived by Yoffe

[0129] , T' is the working environment temperature, α is the Seebeck thermoelectric coefficient, in microvolts / T(K), k is the thermal conductivity of the thermoelectric material in the thermocouple, r is the internal resistance of the thermoelectric device, in ohms, and the total heat conduction of n units of thermocouples in parallel is The series resistance of n thermocouple elements is nr0.

[0130] Therefore, as a thermoelectric device

[0131] So in formula (5), kr is η

[0132] As the conversion efficiency of electrical energy to thermal energy is

[0133] (6) where η DL ​is the Yoffer's derivative efficiency coefficient of the thermoelectric device cooling, n L It is the ratio of high temperature T1 to low temperature T0 during cooling. The meaning of M is the same as above. For the expression of the heating conversion efficiency of the device, due to the error of the literature (1) (3) of Yofei, η DR The form is similar to formula (6).

[0134] From (5) and (6), we can know that the conversion efficiency is related to M and n. L Correlation, that is, correlation with k and r.

[0135] The Joffe theory seeks the extreme value of kr, because kr is in the denominator of the efficiency coefficient, that is, it is believed that the minimum value of Zr can obtain the maximum efficiency coefficient. Joffe uses ρ N ,ρ P , k N , K P (expression of the P arm and N arm materials of k) to find the extreme value of kr. hour;

[0136] Kr has a minimum value, minimum value

[0137] therefore The relationship has not yet been listed, so It does not affect the theory of Kr minimum design; but The ratio will cause the heat conduction area S of k n Reducing heat conduction in a squared relationship is an effective way to improve the performance of thermoelectric devices.

[0138] According to elementary mathematics, kr has a minimum value when equation (7) is satisfied;

[0139] This can be obtained is the minimum value, not affected by Impact; η RD ≈1.2η ND .

[0140] Therefore, when thermoelectric devices save 3-10% of materials (when the material of the N arm remains unchanged, the material of the P arm can be reduced, and when the cross-section is square, the material of both arms is reduced), η RD and η RL (η ND ) have been significantly improved.

[0141] Thermoelectric device optimization is specifically implemented as follows: The device unit consists of a single thermocouple, two temperature electrodes, a transition electrode, and two shared heat exchange radiators at different temperatures. The two thermocouple arms are constructed from two semiconductor materials, an N-type arm and a P-type arm. At the cold-end temperature junction (T0), a metal plate 3-3 serves as a transition electrode, connecting the two arms. The transition electrode plate 3-3 at T0 is combined with the heat exchange cold-end heat exchange plate 1-1 to form the T0 heat exchange chamber. The heat exchange radiator is a highly thermally conductive and insulating plate. The N-type and P-type arms have circular cross-sections. Multiple units are connected in series to form a commercial thermoelectric device.

[0142] The shape of the electric dipole arm is cylindrical. First, according to the product design requirements, determine: the product current value, determine the cross-sectional area s of the P-type electric dipole arm p Size. Set the cross-sectional area of the N-type electric dipole arm to be smaller than the cross-sectional area of the P-type electric dipole arm.

[0143] The process of calculating the cross-sectional area sp of the P-type electric dipole arm is as follows: For example (using the original product TEC-12706), the two electric dipole arms of the original product have a cross-sectional area of 4x4mm squares. The radius of the circle with the same area as the corresponding 4x4mm square cross-sectional area is 2.257mm, and the radius of the circle with the equivalent area is 2.128mm. Take the radius of the electric dipole arm s p is 2.1mm. At this time, relative to the original product device, its circular cross-sectional area is equal to the square cross-sectional area of the original product, that is, the internal resistance of the unit electric dipole arm of the product is The value remains unchanged, and the new product will not affect the change caused by changing the square cross-sectional area to a circular one. Similarly, if the circular (elliptical) area of the N-type galvanic couple arm replaces the square cross-sectional area, the thermoelectric performance of the unit galvanic couple arm will not change or be affected.

[0144] The N-type electric dipole arm will change the cross-sectional area. The basis of its change is the performance of the thermoelectric material. The resistivity ρn≠ρp, ρn>ρp, so S is used. n To regulate r n =r p To ensure r n =r p , when r n =r p Can obtain the current I in the two arms of the electric couple n =I p .according to Figure 5 a Thermoelectric material performance results take different characteristic positions ρ n / ρ p Different S can be obtained at any time due to material properties n As a result, there are different device performance results.

[0145] There is a reasonable distance between the N and P electric dipole arms. It is feasible to keep the arm distance at the original size of about 4mm.

[0146] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A thermoelectric device, characterized in that: A unit of the thermoelectric device is composed of a pair of unit thermocouples, two metal temperature electrodes (3-1, 3-2), a pair of thermocouples connected by a transition electrode plate (3-3), and two common heat exchange heat sinks with different temperatures; the thermocouple's two arms are composed of two semiconductor materials, an N-type thermocouple arm and a P-type thermocouple arm, and are connected at the cold or hot end temperature joint at a temperature of T0 or T1 by a metal thermocouple transition electrode plate; the T0 transition electrode plate is combined with the heat exchange cold or hot end heat sink (1-1) to form a T0 end heat exchange chamber; the T1 temperature end, the N-type and P-type thermocouple arms at this end are respectively connected to the metal electrodes, which is the output electrode end of the thermoelectric device; The heat exchange heat sink is a high heat transfer and insulating plate. The cross-sections of the N-type and P-type electric couple arms are circular or elliptical. Multiple units are connected in series to form a thermoelectric device.

2. The thermoelectric device according to claim 1, wherein: The cross-sectional area of the N-type electric dipole arm or the P-type electric dipole arm changes, and the basis for the change is the thermoelectric material performance ρ n ≠ρ p , ρ n >ρ p , so the area S of N-type electric dipole arm or P-type electric dipole arm is used n To regulate r n 、r p To ensure r n =r p , when r n =r p Can obtain the current I in the two arms of the electric couple n =I p .

3. The thermoelectric device according to claim 2, characterized in that: The cross-sectional area of the N electric dipole arm is set to be larger than the cross-sectional area of the P electric dipole arm.

4. The thermoelectric device according to claim 3, characterized in that: The cross-sectional area of the N electric dipole arm is 3-20% greater than the cross-sectional area of the P electric dipole arm.

5. The thermoelectric device according to any one of claims 1 to 3, characterized in that: The cross-sectional area of the N electric couple arm is larger than the cross-sectional area of the P electric couple arm by 13±3%.

6. The thermoelectric device according to any one of claims 1 to 3, characterized in that: The electric couple arm in the thermoelectric device is cylindrical.

7. The thermoelectric device according to any one of claims 1 to 3, characterized in that: The arcs at both ends of the "transition connecting plate" of the electric couple arm in the thermoelectric device are also connected by arc matching.

8. The thermoelectric device according to any one of claims 1 to 3, characterized in that: The edges and corners of all electric couple arms and joints in the thickness direction are optimized to be arcs or obtuse angles.

9. The thermoelectric device according to any one of claims 1 to 7, characterized in that the device In the structure, the current directions of the transition electrode plates of all the electric dipole arms of each unit are opposite; the current directions in the transition electrode plates of adjacent units are opposite.

10. The thermoelectric device according to claim 9, characterized in that: There is a reasonable distance between the electric dipole arms to reduce the electromagnetic interference of the adjacent inductive magnetic fields on the carriers in the electric dipole.

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