High-Throughput Manufacturing of Flexible Thermoelectric Generators for Low- to Medium-Temperature Applications Based on Nano-Silver Bonding

The melting point of the commercial soldering materials is a limiting factor for the functionality of the thermoelectric generators (TEGs) in medium-temperature ranges higher than 200 °C. Hence, using a proper bonding method which could be formed at lower temperatures and withstand higher temperatures is inevitable to unlock the full potential of the commercial thermoelectric materials. Nano-silver bonding is known as the 'low-temperature joining technique' due to its lower processing temperature compared with the other conventional bonding approaches. This study is focused on presenting a fabrication process of flexible TEGs using nano-silver (Ag) paste bonding. The pellets of thermoelectric materials were prepared by wire cutting of bismuth telluride ingots in desired sizes. The electrical interconnects between the thermoelectric legs are nano-silver paste traces printed by a digitally control dispenser printer. Reliability of the thermoelectric module was evaluated from room temperature up to 300 °C as well as conducting the cyclic bending test. The proposed fabrication technique is similar to the flexible hybrid electronics (FHE) concept, which is scalable for high-throughput manufacturing, such as roll-to-roll or sheet-to-sheet printing.