Low-temperature co-fired ceramic-based thermoelectric generator with cylindrical grooves for harvesting waste heat from power circuits

This paper investigates the optimal design permitting to recover thermal heat released from electronic power components mounted on ceramic substrates. Accordingly, the methodology and the characterization of thick-film/LowTemperature Co-fired Ceramic (LTCC)-based multilayer thermo-electric micro-generators (TEGs) fabrication were detailed. Hence, two different TEGs, based on the Seebeck effect, with different thermocouples materials, Ag/Ni and Ag/PdAg, were fabricated, simulated, analytically studied and compared. Each designed generator contains 104 thermocouples, with 300 mu m-width and space between them. The required heating was produced by a meander-shaped planar heater, simulating the presence of an electronic power device. As well, two heaters are compared, made by Ni and PdAg, and each one is tested in the absence/presence of cylindrical grooves added on the backside of the LTCC substrate. It has been shown that adding grooves around the hot element allows an average improvement of 160% of the temperature difference along the generator. Concerning TEGs, Ag/PdAg-based TEG was able to generate a higher output power of 81 mu W for a temperature difference of 114 degrees C, than the Ag/Ni-based TEG with an output power of 4.6 mu W at Delta T = 62 degrees C. The conversion efficiency was 0.5% and 0.08% for the Ag/PdAg-based and the Ag/Ni-based TEG, respectively.