Thermoelectric properties of FeSi₂ thermoelectric conversion modules sintered with Ag joint plates by spark plasma sintering method

To achieve high performance of thermoelectric conversion module, it is important that the contact electric resistance between thermoelectric element and electrode is decreased. The manufacturing method to perform sintering of FeSi₂ powder and joining of the sintered body with Ag metal plates at the same time was examined by using SPS(spark plasma sintering) method. The Ag plates were successfully joined to FeSi₂ element by this process. In addition, it was able to lower the resistance of thermoelectric conversion module because the contact electric resistance between the FeSi₂ element and the Cu electrode was decreased by joining Ag plates. The thermoelectric conversion modules with various element heights were produced by this process, and the performance of the modules was evaluated under several temperature differences. The most suitable thermoelectric module height, 5 mm, was decided by investigating relations of the module height and the performance. The FeSi₂ thermoelectric conversion module consisting of 50 pairs of p-n elements was produced using an element with 5 mm height, and the performance was measured. As a result, the maximum electric power of FeSi₂ thermoelectric conversion module of 50 pairs was 1.70 W in the condition of heating temperature at 873 K and/or cooling temperature at 293 K.