Voltage–Current Curves to Characterize Thermoelectric Generators

Abstract

There are many ways to experimentally characterize thermoelectric generator (TEG) performance, but most methods provide an incomplete picture. The authors propose using voltage–current (V–I) curves generated at two different thermal conditions to provide an estimation of maximum power, optimum efficiency, ZT of the device, and thermal resistance due to ceramics and thermal interface materials on the outside of the thermoelectric material (HSR). The two thermal conditions are both steady state, electrically open in one case and electrically shorted in the other, and the heat flow into the device is adjusted to keep the hot-side and cold-side temperatures of the exterior of the module the same in both thermal conditions. The V–I curves are generated from four data points by instantaneously changing the external electrical load such that the TEG does not have time to respond thermally. After these two V–I curves are generated, the performance at any electrical condition can be predicted for the given hot-side and cold-side device temperatures. The authors present experimental data for a bismuth telluride (Bi₂Te₃) device as verification of this characterization method.