Optimization Of Thermoelectric Module Based On Nitride Thin Film Thermoelectric Materials

In recent years,with the continuous development of social industrialization and science and technology,human demand for energy is growing,fossil energy is gradually exhausted,but the demand for electric energy is still increasing,it makes people pay more attention to the efficient use of energy which because of the energy shortage caused by excessive energy consumption and environmental problems caused in the process,develop renewable new energy and explore new efficient energy saving energy technology to meet the growing demand for energy use is the strategic focus of the current scientific community and even various countries.Thermoelectric power generation technology is a safe,pollution-free,green and environment-friendly power generation technology,which uses the thermoelectric effect of thermoelectric semiconductor materials to convert low-grade energy such as solar energy,geothermal energy,waste heat of automobile exhaust and industrial waste heat into electric energy.However,compared with the traditional power generation technology,the power generation efficiency of thermoelectric technology is generally not high,which seriously restricts its rapid development and large-scale application.One of the fundamental reasons that restrict the efficiency of thermoelectric power generation is that the thermoelectric conversion performance of thermoelectric materials is not ideal.Based on the above situation,the development of high-performance thermoelectric materials and optimization of the performance of thermoelectric module can effectively improve the application value of thermoelectric technology.The main work of this dissertation is as follows:1.Introduced the basic principles of thermoelectric power generation and the research methods to improve the performance of thermoelectric power generation.One is the three thermoelectric power generation effects,namely Seebeck effect,Peltier effect,and Thomson effect;the other is the main parameters for evaluating thermoelectric power generation performance.The thermoelectric figure of merit,output power and thermoelectric conversion efficiency;third,the thermoelectric performance research calculation methods mainly include density functional theory and Boltzmann transport theory.2.Using Matlab/simulink to build a simulation model of the thermoelectric power generation module,and keep the other parameters fixed to ensure the same conditions,the influence of different thermoelectric performance materials on thermoelectric module performance is analyzed.3.Based on density functional theory(DFT)and semi-classical Boltzmann transport theory,using full potential linearized augmented plane wave(FP-LAPW)method and approximation methods such as GGA and TB-m BJ to establish and optimize the crystal structure and calculate the electronic structure,thermoelectric transport properties analysis and other steps,and gradually calculate the thermoelectric parameters such as Seebeck coefficient,electrical conductivity,electronic thermal conductivity and lattice thermal conductivity of monolayer(M=Zr,Hf)MNX(X=Cl,Br)which as a function of temperature and carrier concentration.4.The thermoelectric properties of thermoelectric materials vary in different temperature ranges.In this paper,three temperature ranges are selected,namely 300K-400 K,800K-900 K and 1300K-1400 K.The highest thermal power value of thermoelectric materials is found in three temperature ranges.The corresponding Seebeck coefficient,electrical conductivity and thermal conductivity are obtained according to the temperature and carrier concentration corresponding to the Maximum ZT value,then substitute the thermoelectric power generation model for comparative analysis,and find the optimal output power and thermoelectric conversion efficiency of thermoelectric power generation in different temperature ranges,and provide application basis for improving the working performance of thermoelectric power generation modules...