Macro-Scale Patterning for Hierarchically Designed Thinner Peltier Sheets

Towards the Global Cooling Pledge launched on CoP28 at Dec. 5, 2023, reducing over 60% greenhouse gas emissions from the cooling sector [ref. 1], thermoelectrics (TEs) has a great potential because Peltier human cooling devices directly cool down the body temperature not the entire room temperature to save 10-times energy consumption compared to air conditioners only [ref. 2,3]. To slim the thickness and enhance the contacting body area when using the same amount of TE materials [ref. 3,4], we have been developing thinner Peltier sheets using sticky TE materials [ref. 5,6] based on a hierarchical multi-component strategy turning element composition of TE particles for high Seebeck coefficient at atomic scale [ref. 7], controlling the surface of TE particles for small interfacial electric resistance at nano scale [ref. 7], and minimizing thermal conductivity and absorbing mechanical bending stress by hybridizing organic solvent with the TE particles [ref. 6] and adopting ultra-thin high performance foam at micro-scale [ref. 3]. Instead of the benefits on flexibility and in the rate of heat transfer [ref. 3,4], however, Peltier sheets tend to ruin the cooling performance. Since thinner design requires higher current at the maximum operating point, more Joule heat is generated at the electrodes sandwiching the TE materials to reduce the temperature difference formed within the TE materials based on Peltier effect. Especially, narrow electrode patterns adopted for the TE generation modules to accumulate the thermopower based on Seebeck effect in series and drive booster circuits [ref. 5] generates Joule heat in general. Through surveying various pattern combination between sticky TE materials and electrodes at macro-scale, herein, we propose a different pattering rule than that for TE generation modules.<br/><br/>[ref. 1] https://news.un.org/en/story/2023/12/1144382<br/>[ref. 2] Itao et al. J Jpn Soc Precis Eng 2016;82:919-924 (in Japanese).<br/>[ref. 3] Satoh et al. MRS Adv 2023;8:781-786.<br/>[ref. 4] Satoh et al. MRS Adv 2023;8:446-450.<br/>[ref. 5] Satoh et al. Sci Technol Adv Mater 2018;19:517-25.<br/>[ref. 6] Satoh et al. MRS Adv 2020;5:481-487.<br/>[ref. 7] Satoh et al. Soft Sci 2022;2:15.