A novel battery system for using in extremely low temperature conditions

A module with 11 thin film battery (TFB) stacks was fabricated to investigate its internal resistance and charging characteristics to a real capacitor with 150 μF. Each cell consisted of thin layers of LiCoO2, LiPON and Li on a ceramic substrate, and each layer was deposited by radio frequency (RF) + direct current (DC) hybrid magnetron sputtering, RF reactive sputtering, and thermal evaporation, respectively. In order to increase the effective surface area of the TFB in a limited small volume, 11 cells were stacked and connected in parallel. By designing the thermal switch with a heating source, its capacitor charging performance was well maintained, even at temperatures below −30 °C, as well as at room temperature. Charging to greater than 4 V was completed within 0.06 sec at room temperature and within 0.13 s at −30 °C due to the heat-up process. A novel battery system consisting of the TFB module with a thermal switch and a heating source proved to be a promising substitute for the ampoule type reserve battery in small sized electrical fuses, even at very low temperatures.