Assessment of Artificial Anisotropic Materials for Transverse Thermoelectric Generators

Abstract

By alternately stacking layers of two materials that differ in their Seebeck coefficient and electrical and thermal conductivity, a composite material with artificial anisotropy of thermal and electrical transport properties is formed. Due to the transverse Seebeck effect, a thermoelectric (TE) voltage is generated perpendicular to a temperature gradient ΔT, that is applied at a certain angle φ with respect to the stacked layers (0° < φ < 90°). The TE properties of layered artificial anisotropic materials are described analytically using existing concepts and extending the available definitions to develop a consistent image of anisotropic media for TE energy generation. Based on these analytical descriptions, the TE performance of ceramic oxide–metal composites and transverse TE generators (TTEG) made of them are numerically calculated and presented in contour plots. These so‐called micro‐ and macro‐Babin plots map the influence of internal geometric parameters, i.e., the layer thickness ratio and the angle φ of the applied temperature gradient with respect to the stacked layers. Based on these diagrams, the optimal TTEG geometry can be narrowed down in a simple and fast way. In addition, the diagrams are used for a material screening to evaluate the suitability of different oxide ceramics for use in a TTEG.