Powering wireless sensors: Microtechnology-based large-area thermoelectric generator for mass applications

In a thermoelectric generator (TEG), hundreds of individual couples of two thermoelectrically dissimilar materials are electrically connected in series, but thermally in parallel within a given heat flux. Thus, the devices generate a few 10s of mW and may, for example, be used in wireless sensor applications. Apart from highly integrated costly batch fabricated micro TEGs for niche applications, commercially available Peltier/TEG modules are assembled manually from bismuth telluride (Bi₂Te₃) blocks. The present work aims at new designs of metal (nickel-copper) and semiconductor based TEGs. The proposed combination of electrochemical deposition with known printed circuit board (PCB) techniques will facilitate industrial mass-production. Our first fully packaged prototype consists of 29.5 Ni/Cu couples per cm² at an effective area of 13 cm². At a temperature drop of 36 K across the packaged device, it generates an output power of 450 μW (~27 nW/K²/cm²). The thermoelectric characterization is performed in a 200 W test setup.