Comprehensive impedance spectroscopy equivalent circuit of a thermoelectric device which includes the internal thermal contact resistances

Thermoelectric devices are widely used as solid-state refrigerators and have potential energy generation applications. Their characterization is key to develop more efficient monitor their performance. Electrical impedance spectroscopy has been proved be a useful method for the of thermoelectric modules. However, deviations from current models still exist in experimental results, especially high frequency part spectrum, which limits its use. Here, we present new comprehensive model (equivalent circuit) covers all phenomena that affects module performance, it able explain observed deviations. The equivalent circuit includes, additions, thermal influence metallic strips (electrodes), combined with contact resistance between outer ceramic layer. Moreover, accurate spreading-constriction element, considers variation heat flow radial direction at surfaces, also developed. was perform fittings measurements modules fabricated by different manufacturers. From fittings, possible identify, among other properties, internal resistances, whose direct determination very challenging. Thermal resistivities strips/thermoelectric elements interface range 2.20 × 10-6-1.26 10-5 m2KW−1 were found. An excellent identified strips/ceramic layers. This opens up possibility using powerful tool evaluate, monitor, identify issues devices.