Evaluation and Optimization of A New Flexible Thermoelectric Cooling Device

In the past decade, wearable and flexible thermoelectric cooling devices have emerged as promising solutions for active cooling, particularly in military contexts to mitigate heat stress among soldiers, as well as for diverse military and civilian applications. However, the widespread adoption of commercially available ceramic-packaged thermoelectric devices (TED) has been hindered by their rigidity and limited cooling efficiency. To address these issues, we have recently developed a highly flexible TED utilizing bismuth telluride-based TE pillars, thin copper electrodes, and insulating Ecoflex rubber. Multiple TED prototypes were fabricated with Ecoflex films of varying thicknesses. These TEDs, when coupled with efficient and flexible heatsinks made from Ecoflex, flexible Cu foam, thermally conductive aluminum nitride (AlN), and a phase-change material (PCM), demonstrated remarkable performance. They effectively lowered skin temperature from 36°C to a comfortable 32°C for a duration of at least 23 minutes, even in ambient temperatures set at 37°C. The fabricated TEDs underwent thorough characterization and evaluation for their active cooling capabilities, in addition to assessment alongside various heatsinks. Their flexibility and durability were also examined. Detailed discussion on the fabrication process and analysis of these devices will be provided.