基于纳米复合材料的热电发电器件热量传递和能量转换机制研究

The thermoelectric generator, which directly converts heat to electricity, has the advantages of small volume, light weight, no noise, accuracy and reliability. However, relatively small conversion efficiency limits its widely application. In nanocomposites, due to the introduction of the quantum effect and the low-energy carrier filtering effect, the Seebeck coefficient can be increased effectively, and the thermal conductivity could be strongly reduced due to the mode mismatch and interface scattering of the phonon at the interfaces. Therefore nanocomposites can provide enhanced figure of merit and has been applied in the thermoelectric generator. We will firstly study the electron/hole and phonon transport mechanisms in nanocomposites and obtain the dependence of the figure of merit on different material parameters. Then we will investigate the production mechanisms of Joule heat, Thomson heat and Peltier heat, the heat transfer process, and the energy conversion mechanism induced by Seebeck effect in the thermoelectric generator by including the influences of various relevant factors together with their interaction with each other. Finally, by linking the microscopic investigation of nanocomposites and the macroscopic design of the thermoelectric generators, we will obtain the influence of the microscopic parameters of the nanocomposites to the macroscopic properties of thermoelectric generators and give the feasible way to optimize the efficiency of the thermoelectric generators. These studies will provide the fundamental theoretical guidance for the application of thermoelectric generators with nanocomposites included, and will also be helpful for exploring enhanced performance thermoelectric generator.

热电发电器件能实现热能到电能的直接转化，具有体积小、重量轻、无噪声和精确可靠等优点，但较低的热电转换效率限制了它的广泛应用。纳米复合材料中量子效应的引入及对低能载流子的过滤效应可以有效增大Seebeck系数、同时界面声子模式不匹配和界面散射降低了热导率，因此可以实现较高热电优值而被引入热电发电器件。本项目拟联系纳米复合材料性能的微观研究和热电发电器件的宏观设计，从纳米复合材料中电子/空穴和声子输运机制出发，分析微观参数对其热电优值的影响；综合考虑相关因素的影响及协同作用，研究热电发电器件中焦耳热、Thomson热和Peltier热的产热效应和传热过程以及Seebeck效应引起的能量转换机制，厘清纳米复合材料微观参数对热电发电器件宏观性能的影响，探寻优化热电发电器件性能的可行途径。本项目旨在为基于纳米复合材料的热电发电器件的应用提供必要的基础性科学依据，对热电发电器件性能的提高进行有益探索。

热电发电器件能实现热能到电能的直接转化，具有体积小、重量轻、无噪声和精确可靠等优点，但较低的热电转换效率限制了它的广泛应用。本项目联系纳米复合材料性能的微观研究和热电发电器件的宏观设计，按照热电材料输运机制及性能调控-热电器件产热与传热机制及性能优化-热电发电系统能量传递及系统设计的思路，研究了热电材料与器件中的能量输运和能量转换机制。我们研究了有机无机纳米复合热电材料和无机非晶材料中的热电输运性质，揭示了界面和拓扑网络结构在复杂固体体系中对热电性质影响的规律；厘清了汤姆逊效应对热电输运性质的影响，发现汤姆逊效应使仅通过优化材料热电优值提升热电发电器件效率的效果变差；探讨了界面热阻的比值对热电发电器件中能量输运的影响机制，通过调控界面热阻比值优化了热电发电器件性能；发现桶状热电发电器件在环状热源条件下性能优于平板型热电发电器件，并进一步优化了桶状热电发电器件的翅片数量和几何位形以提升其能量转换效率和输出功率；设计了相变材料、纳米流体与热电发电器件耦合构成的复合发电系统，给出了相变材料与热电材料性能匹配的规律，厘清了冷端温度对系统总输出电能的影响。通过本项目的实施，发表了标注本项目的科研论文24篇，其中SCI论文13篇、EI论文2篇、中文核心3篇；申请及获批专利10项；发表会议论文2篇；项目负责人受邀在国际和国内学术会议做分会邀请报告2次、作为大会秘书长举办了第二届中国热物性学术会议，项目组成员共参与各类学术交流40余人次；项目组两人在项目期间晋升副高职称；项目负责人王元元教授获得上海市教委“曙光学者”项目支持；培养了八位研究生，其中四位已获得硕士学位。本项目的完有助于深入理解热电发电器件中能量输运和能量转换的基本物理机制，同时对热电发电器件性能的提高进行了有益探索。