Coin-size coiled-up polymer foil thermoelectric power generator for wearable electronics

A coiled-up thermoelectric micro power generator is presented using metal films sputtered on a thin polyimide foil. The principle of coiling-up yields higher voltages at a smaller generator area. Design optimizations were made for maximum long-term power output using the human body as heat source. It is shown that for low-power electronics like a wrist-watch even simple materials are sufficient and allow lowest-cost production, e.g. screen printing. Thermoelectrical screen-printing pastes were developed and results of first screen printed thermocouples are given.