A fast-heat battery system using the heat released from detonated supercooled phase change materials

Highlights: • A passive but rapid battery heating strategy with thermal release of subcooled PCM. • The stable subcooling of PCM was used to preserve the latent heat. • An effective trigger device for solidification of subcooled PCM is designed. • The heating rate of this method is up to 7.5 °C/min. • The discharge capacity and power of the battery were improved by 9.87% and 7.56%. A heating strategy has been developed for the battery operated at low temperature, which can intelligently control the thermal storage and release of an inorganic phase change material (PCM): CaCl2·6H2O - carboxymethyl cellulose (CMC). With the 0.5 wt % CMC content, this PCM (melts at 25–30 °C) becomes stable in the subcooled state, making it possible to be used as the subcooled liquid at 5 °C to store the heat generated by the battery. The thermal energy stored in the subcooled PCM can be detonated to release by triggering the PCM to crystalize with a special device. The instant crystallization of this subcooled PCM heats the battery rapidly-which is at a rate up to 7.5 °C/min, higher than the battery without PCM (0.8 °C/min) or the battery with the no subcooled PCM(0.4 °C/min). The discharge capacity and power can be improved by 9.87% and 7.56%. This work presents a new method of heating by switching the subcooling of PCM on/off, which extends the application of PCMs to battery heating under low temperatures. This energy-free but efficient method could provide a better alternative to most active heating systems.