温差发电模块面积比功率实验优化研究

同位素温差发电器是目前深空探测航天器广泛采用的电源装置。为优选温差发电模块构型、提高模块的输出功率和面积比功率,制备了具有不同热电元件截面积的碲化铋基温差发电模块。通过建立的实验测试系统,测量了多种温差条件下发电模块的输出功率随负载的变化。实验结果表明:当模块包含的热电元件(p–n结)对数一定时,热电元件的截面积越大、模块占空比越高,则模块输出功率越高、匹配负载越小;在热源温度450 K、热沉温度300 K的条件下,测得热电元件截面积为1.6 mm×1.6 mm、占空比为0.406的发电模块的最大面积比功率约为0.282 W·cm~(-2)。最后,对理想与实际情况下,占空比为1时的模块面积比功率进行了分析。

Experimental optimization of the area-specific power for thermoelectric modules

Radioisotope thermoelectric generators (RTG) are widely applied in spacecraft for the deep space exploration. In order to enhance the output power and the area-specific power of the thermoelectric modules, Bi₂Te₃-based thermoelectric modules with different thermoelement cross-areas are prepared. An experiment setup is built to measure the output power of the thermoelectric modules as well as the load resistances under conditions of different temperature differences. According to the test results, when the number of p-n junctions is specified, higher thermoelement cross-areas and higher occupancy ratios result in higher output powers and lower matched loads. With a module with a thermoelement cross-area of 1.6 mm×1.6 mm and an occupancy ratio of 0.406, the maximum area-specific power around 0.282 W·cm^-2 is reached when the temperatures of the heat source and the heat sink are 450 K and 300 K, respectively. In ideal and practical cases, the area-specific powers of the modules with occupancy ratio of 1 are analyzed.