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Bi0.4Sb1.6Te2.7Se0.15S0.15 alloy thermoelectric material is introduced in this paper for thermoelectric power generation in the temperature range of 300–500 K. To evaluate the proposed material in a practical service environment, a BiSbTeSe-based thermoelectric module (TEM) with 254 thermoelectric elements is fabricated. Simulations and experiments are undertaken to assess the performance of the BiSbTeSe-based TEM under two different cases of constant heat source and heat flow. An analysis of heat transfer is conducted based on the temperature distribution of different cross-sections. Compared with a conventional Bi2Te3-based TEM, the proposed TEM can output a higher voltage when the temperature difference is higher than 60 K, especially in the heat flow case. When the temperature difference is 200 K, the open-circuit voltages are 10.90 V and 9.79 V, and the maximum output power is 8.8179 W and 7.1279 W under the constant temperature and heat flow cases, respectively. The maximum power is achieved when the load resistance is slightly higher than the internal resistance due to the effect of Peltier heat. The average deviation between the experimental values and simulation results is approximately 5.6%. The experiments verify the rationality and validity of the simulation model. This study reveals that the performance of the proposed BiSbTeSe-based alloy material is better than that of conventional bismuth telluride alloys within the range of 300–500 K. In addition, compared with constant heat thermal boundary conditions, it is more suitable for the heat flow case. [ABSTRACT FROM AUTHOR]

Described herein is a detailed and comprehensive multiphysics model of a thermoelectric generator (TEG). The one-dimensional model uses electrical–thermal analogies solved for transient response using SPICE. There are many advantages and applications of thermoelectric generators. Wider use and application advancements are generally limited by the tools available for engineering and scientific studies. Currently, available modeling tools are limited by some combination of speed, platform capabilities, or missing physics that are not used or assumed to be negligible. The TEG module model herein is made up of two sub-models, the thermoelement model and the non-thermoelement model. Rather than a lumped thermoelement model, the model herein makes use of distributed physics that include the following: Thomson effect, temperature dependence, mass, Joule heat, thermal resistance, Seebeck effect, and electrical resistance. The non-thermoelement model takes into account temperature dependence and simulates Joule heat generation, thermal resistances, thermal and electrical interface resistances, and mass for and between the ceramic, copper, and solder. The comprehensive model herein was correlated to experimental data that simultaneously varied electrical current and hot and cold side temperatures with time. Very minimal adjustments to reported thermoelectric properties were required to almost perfectly match the experimental transient power output. The effects of the non-thermoelement model, distributed Thomson effect model and distributed temperature dependent property model were quantified. The model ran very quickly, taking 2.5 real-time seconds to run a 4000 s transient simulation. [ABSTRACT FROM AUTHOR]

We report about the modelling of spark plasma sintering of a line of thermoelectric materials. A significant difference of sintering temperature ΔTs from 15 K to 110 K was found in the samples studied. The Peltier effect on the graphite-thermoelectric interfaces results in such temperature difference. The rise of sintering temperature leads to the ΔTs increase. ΔTs in the vertical direction is 2-3 times higher than in the radial one. Electric insulation modelled in the horizontal graphite-thermoelectric interfaces reduced ΔTs in all the types of numerically studied samples by 59-92%. [ABSTRACT FROM AUTHOR]

A comprehensive study of the mechanisms of heating and cooling originating from an electrical current in semiconductor devices is reported. The variation in temperature associated with the Peltier effect is not related to the presence of heat sources and sinks if the heat flux is correctly determined. The Thomson effect is commonly regarded as a heat source/sink proportional to the Thomson coefficient, which is added to the Joule heating. In the present work, we will show that this formulation of the Thomson effect is not sufficiently clear. When the heat flux is correctly defined, the Thomson heat source/sink is proportional to the Seebeck coefficient. In the conditions in which the Peltier effect takes place, the temperature gradient is created, and, consequently, the Thomson effect will occur naturally. [ABSTRACT FROM AUTHOR]

Atmospheric water may condense on the surface of Bi2Te3-based compounds constituting the Peltier module, depending on the operating environment used. In the stage of disposal, Bi2Te3-based compounds may come into contact with water in waste disposal sites. There are very few publications about the influence of condensed water on Peltier modules. Bi2Te3-Sb2Te3 or Bi2Te3-Bi2Se3 pseudo binary system compounds are used as p-type material or n-type material, respectively. The lattice distortion will be induced in the crystal of Bi2Te3-based compounds by element substitution due to the reduction in their thermal conductivity. However, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds remains unclear. In this study, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds with practical compositions has been investigated. Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 was prepared by the vertical Bridgman method. The electrochemical properties at room temperature were evaluated by cyclic voltammetry in a standard three-electrode cell. The working electrolyte was a naturally aerated 0.6 or 3.0 mass% NaCl solution. From the tendency for corrosion potential for all the samples, the corrosion sensitivity of ternary compounds was slightly higher than that of binary compounds. From the trend of current density, it was found that Bi0.5Sb1.5Te3 had a corrosion resistance intermediate between Bi2Te3 and Sb2Te3. On the other hand, corrosion resistance was affected despite a small amount of Se substitution, and the corrosion resistance of Bi2Te2.85Se0.15 was close to or lower than that of Bi2Se3. From the observation results of the corrosion products, the trends of morphology and composition of corrosion products for Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 were consistent with those of Sb2Te3 or Bi2Se3, respectively. From the results of x-ray photoelectron spectroscopy for the electrolyte after testing, the possibility that a corrosion product diffuses to the environment including the salt was suggested in Bi0.5Sb1.5Te3. However, the amount of dissolved corrosion product was very low, and the chemical stability of the corrosion product was not changed or improved by element substitution. [ABSTRACT FROM AUTHOR]

Filled skutterudite is a promising material for thermoelectric power generation because its ZT value is relatively high. However, mass production of high-performance thermoelectric materials remains a challenge. This study focused on the sintering process of thermoelectric materials. Large-diameter n-type (Yb or La, Ca, Al, Ga, In)(Co, Fe)Sb skutterudite sintering bodies with a small thickness were successfully produced by the spark plasma sintering (SPS) method. When direct current flows through the thermoelectric sintering body during the SPS pulse, the Peltier effect causes a temperature difference within the sintering body. To eliminate the Peltier effect, an electrical insulating material was inserted between the punch (electrode) and the sintering body. In this way, an n-type La-filled skutterudite sample with a diameter of 200 mm, thickness of 21 mm, and weight of 5 kg was successfully produced. The thermoelectric properties and microstructures of the sample were almost the same throughout the whole sintering body, and the dimensionless figure of merit reached 1.0 at 773 K. [ABSTRACT FROM AUTHOR]

Based on the Peltier effect, thermoelectric coolers (TECs) have been widely used in solving thermal management issues for semiconductor devices such as semiconductor laser, charge-coupled devices and nanoelectronic circuits with hot-spots. However, performance control mechanisms especially voltage-controlled parameters for TEC still face challenges. In this paper, a standard mathematical model for multi-stage TECs is proposed with thermal resistances from both sides and performance parameters dependent on voltage. The proposed models agreed with experimental results. Compared with the available model, the relative standard deviations between the obtained equivalent thermal conductivity model and experimental results at 25°C and 50°C are decreased by 88.87% and 30.14%, respectively. Also, the relative standard deviations between the proposed thermoelectric figure of merits model and calculated results based on experiments at two different temperatures are decreased by 84.45% and 62.94%, respectively. The results provide a controllable method of thermoelectric characteristics with high accuracy, which can be employed for early thermometric performance estimation for TEC design. [ABSTRACT FROM AUTHOR]

A tubular configuration is a practical form of thermoelectric (TE) device to generate electric power from fluid heat sources as well as to control the temperature of fluid media by Peltier effect. Here, we report the realization of a tubular π-type TE module which enables both power generation and Peltier refrigeration. The tubular module was obtained by stacking ring-shaped constituents in the axial direction, followed by simultaneous spark plasma sintering and joining processes. The experimentally-observed maximum power-density and efficiency are 0.9 kW/m and 2.2%, respectively, when a small temperature difference (Δ T) of 85 K was maintained using hot and cold water. Peltier refrigeration of the tube outer surface is also demonstrated. The obtained maximum Δ T and the cooling power density are Δ T = 49 K and 32.6 kW/m, respectively. The present results indicate the high feasibility of this tube as a fluid-mediated practical TE module. [ABSTRACT FROM AUTHOR]

There has recently been much progress in the development of materials with higher thermoelectric performance, leading to the design of thermoelectric devices for generation of electricity and for heating or cooling. Local heating can be achieved by current flow through an electric resistance, and local heating and cooling can be performed by Peltier heating and cooling. In this study, we developed computer software that can be used to predict the Seebeck and Peltier effects for thermoelectric devices. The temperature, electric potential, heat flow, electric current, and coefficient of performance were determined, with the objective of investigating the Peltier effect in a thermoelectric device. In addition to Peltier heating and cooling, Joule and Thomson heating were quantitatively evaluated for the thermoelectric device. [ABSTRACT FROM AUTHOR]

Integrating a thermoelectric cooler (TEC) into the engine cooling system has various advantages including reducing additional mechanical parts, and saving energy and space for automotive applications. Based on performance parameters of the engine and thermoelectric modules, three different TEC configurations called plate-shape, stripe-shape, and diamond-shape are constructed with development of simulations of the different TECs and the performance of the circulating coolant. Based on these simulations, the velocity, pressure, and temperature fields of the coolant are obtained for further research. Besides, the temperature of the TEC and the output power of the thermoelectric generator (TEG) are acquired experimentally. Comparing the working performance of the different TECs, the simulation and experimental results show that the TEG using the diamond-shaped TEC achieves a relatively ideal performance. Finally, some measures are proposed to improve the cooling system, providing guidelines for future research. [ABSTRACT FROM AUTHOR]

The performance of thermoelectric modules for energy-harvesting applications is investigated, and a model is presented to predict module performance. Derived from energy conservation equations, the model predicts module performance by solving for the temperatures at both ends of the thermoelectric materials within a module. Unlike traditional methods, the model accounts for the effect of electrical current with respect to the load resistance by considering additional heat transfer by Joule heating and the Peltier effect. This establishes a nonlinear quadratic form of temperatures which can be solved by an iterative numerical solution. The model is extended to predict the performance of energy-harvesting systems, which may include connection of multiple thermoelectric modules in series to meet the necessary power requirements. However, a key issue with multiple module connection is the power reduction that arises when there are significant differences in module properties and/or the corresponding external conditions to which each individual module is exposed. Power reduction is thus investigated, as in some cases the overall power output for multiple modules can be less than the power output of a single module. For validation and comparison of the model, experimental support is provided for the case of two commercial thermoelectric modules connected in series. The model also provides optimum load resistances, and a system optimization of the number of modules for a designated heat sink to maximize power generation. The overarching goal of this work is to provide performance prediction and optimization considerations for actual thermoelectric energy-harvesting systems. [ABSTRACT FROM AUTHOR]

This study investigates electromigration in BiTe thermoelectric (TE) material systems and the effectiveness of the diffusion barrier under current. The Peltier effect on the interfacial reaction was decoupled from the effect of electromigration. After connecting p- and n-type BiTe to Sn3Ag0.5Cu (SAC305) solders, different current densities were applied at varying temperatures. The BiTe samples were fabricated by the spark plasma sintering technique, and an electroless nickel-phosphorous (Ni-P) layer was deposited at the solder/TE interfaces. The experimental results confirm the importance of the Ni diffusion barrier in joint reliability. Intermetallic compound layers (Cu,Ni)Sn and NiTe formed at the solder/Ni-P and Ni-P/substrate interfaces, respectively. The experimental results indicate that the mechanism of NiTe and (Cu,Ni)Sn compound growth was dominated by the Peltier effect at high current density. When the current density was low, the growth of NiTe was affected by electromigration but the changes of thickness for (Cu,Ni)Sn were not obvious. [ABSTRACT FROM AUTHOR]

Reducing cryogenic heat leaks is critical for superconducting applications. Reduction of heat leak at the terminals is essential for uses with short-length applications, where cryogenic losses at the terminals dominate. We are developing a 200-m-class superconducting direct current (DC) transmission and distribution system (CASER-2), and have used a Peltier current lead (PCL) for heat insulation at the terminals. The PCL consists of thermoelectric elements and copper leads, which enhance the performance of superconducting systems. As DC flows through the current lead, thermoelectric elements on opposite terminations of a superconducting line can be used to decrease the heat ingress to the cryogenic environment ( n-type on one end, p-type on the opposite end). During the current feeding and cooling test, a large temperature difference was observed across thermoelectric elements in the PCL. This demonstrates that we have successfully insulated the heat leak at the current lead. During the fourth cooling test, we established a new PCL design with p-type elements at terminal B, and then compared the performance of the terminals. Several improvements were implemented, including balancing the resistances of the PCL to enhance the stability of the superconducting systems. [ABSTRACT FROM AUTHOR]

New equipment has been developed for evaluating the figure of merit, ZT, on the basis of the Harman method in the temperature range between room temperature and 650 K. In this temperature range, the sample holder in the vacuum chamber has a different construction as compared with the sample holder constructed for the temperature range below room temperature. Several issues that need to be considered, such as compensation for the thermal radiation effect, suppression of heat leakage from the lead wires, and the setup method for the lead wires on the sample, are examined in the considered temperature region. Evaluations of ZT are successfully made for typical thermoelectric materials, (Bi,Sb)Te and CeFeCoSb. We then demonstrate that the influence of thermal radiation between the high- and low-temperature edges of the sample induced by the Peltier effect on the estimated value of ZT is negligible at around 600 K. Furthermore, the change in the thermoelectric properties due to repetition of the thermal cycle is studied, and a typical hysteresis behavior is observed in the considered thermoelectric materials. It is revealed that heating the sample to a high temperature causes a change in its thermoelectric properties, which one must take into account for practical applications of thermoelectric materials. [ABSTRACT FROM AUTHOR]

We consider thermoelectric effects in a pseudo-one-dimensional electron gas (P1DEG) with a spin-orbit interaction (SOI). The SOI splits the dispersion relation of the P1DEG into subbands with an energy gap. We find quantum oscillations in transport coefficients, which coincide with the locations of the subband edges, as a function of the electrochemical potential. [ABSTRACT FROM AUTHOR]

It is observed that the interfacial reactions in Sn/Co couples are different at the anode and cathode sides as a result of temperature differences caused by the Peltier effect. The Sn/Co interfacial reactions were examined at 180°C with the passage of an electric current of 5000 A/cm2. The reaction phase was CoSn3. The reaction layer at the Co/Sn anode interface in which the electrons moved from Co to Sn was thicker than that at the Sn/Co cathode interface, but this phenomenon could not be reasonably accounted for using the electromigration effect. The temperature of Sn at the Co/Sn anode interface was 4.5°C higher than that at the Sn/Co cathode interface with the passage of 5000 A/cm2 electric current at 180°C. Temperature differences were determined with a carefully designed cathode–anode switching experiment using thermocouples, and the results were confirmed with thermal infrared microscope measurements and calculated results based on heat transfer models. [ABSTRACT FROM AUTHOR]