Development of thermoelectric power system utilizing waste heat from vehicles

本课题旨在利用汽车余热实现热电发电系统。从实验和理论两方面得到的结果总结如下。1)中温范围热电功率模块组装工艺采用金属氢化物或积氢金属箔，实现了热电元件（CoSb_3、Yb-CoSb或Bi_2Te_3）与Cu金属之间牢固的欧姆连接。节理层对Cu元素的迁移起屏障作用。利用钛金属箔研究了热传导AlN陶瓷与Cu的接合过程，以对抗接合处产生的热应力。2)热电材料的过程控制与电子态计算为提高热电材料的性能，研究了CoSb系列、PbTe系列和硅酸盐系列的烧结工艺。此外，对CoSb和硅氧烷的电子态的理论计算不仅解释了实验结果，而且为笼形化合物提供了一个有效的过程。3)带热电模块的单位式热电模块换热器是为了提高热电模块的导热性而设计的。通过对换热器热电特性和热传导特性的数值模拟，可以满足换热器的基本特性。这是由于采用了合适的热回收翅片（在高温侧）和导热凝胶片（在低温侧）。

This research has conducted with aiming to realize thermoelectric power system utilizing vehicle waste heat. Obtained results both from experimentally and theoretically are summarized as follows.1)Assembling process of thermoelectric power module for mid-temperature rangeUsing metal-hydrides or hydrogen-accumulated metal foil, firm and Ohmic joint has been achieved between thermoelectric elements (CoSb_3, Yb-CoSb, or Bi_2Te_3) and Cu metal. The joint layer functioned as a barrier for Cu elements migration. Joint process between thermo-conductive AlN ceramics and Cu was also examined using Ti-metal foil, working against the heat stresses arising at the joint.2)Process control and calculations for electronic states of thermoelectric materialsFor improving the figure of merit of the thermoelectric materials, sintering processes of CoSb series, PbTe, and silliside series were examined. Besides, theoretical calculations for the electronic states of CoSb and silliside not only interpreted the experimental results, but also suggested an effective process for clathrate compounds.3)Unit-type heat-exchanger with thermoelectric moduleUnit-type heat-exchanger with thermoelectric module was designed to improve the heat conduction through the thermoelectric module. According to the numerical simulation for the thermoelectric property and the heat conduction, basic feature of the heat-exchanger was satisfied. This is due to the employment of the suited heat recovery fins (at high temperature side) and a thermo-conductive gel-sheet (at low temperature side).