Power Generation Characteristics of Mg₂Si Uni-Leg Thermoelectric Generator

Abstract

Mg₂Si thermoelectric (TE) elements were fabricated by a plasma-activated sintering method using a commercial polycrystalline n-type Mg₂Si source produced by the Union Material Co., Ltd. This material typically has a ZT value of ∼0.6. A monobloc plasma-activated sintering technique was used to form Ni electrodes on the TE elements. The dimensions of a single element were 4.0 mm × 4.0 mm × 10 mm, and these were used to construct a TE module comprising nine elements connected in series. To reduce the electrical and thermal contact resistance of the module, each part of the module, i.e., the elements, terminals, and insulating plates, was joined using a Ag-based brazing alloy. In addition, to maintain the temperature difference between the top and bottom of the module, a thermal insulation board was installed in it. The observed values of open-circuit voltage (V _OC) and output power (P) of a uni-leg structure module were 594 mV and 543 mW, respectively, at a maximum ΔT = 500 K.