Hydrated Salt Composite Phase Change Materials for Passive Thermal Management and Safety Protection of Lithium-Ion Batteries

ObjectivesWith the development of high power and high energy density batteries, thermal safety has become the key to limit the large-scale application of lithium-ion batteries (LIB), and efficient thermal safety protection technology has become an inevitable development. Therefore, a hydrated salt composite phase change material (CPCM) with high latent heat, high thermal conductivity and two-stage temperature control function is prepared for LIB thermal management and thermal safety protection.MethodsThe thermal physical properties and heat storage process of CPCM are determined by scanning electron microscope test, differential scanning calorimetry analysis and thermal constant analysis. Then, the temperature control effect is studied by combining the thermal performance test, and the best ratio of CPCM is selected.ResultsThe CPCM with an expanded graphite incorporation mass fraction of 10% has a latent heat of 183.7 J/g and a thermal conductivity of 3.926 W/(m⋅K). The latent heat of phase change can absorb heat and quickly transfer to the outside under the condition of high rate discharge of LIB, and the phase change platform lasts for 20-40 min. The CPCM thermochemical heat storage can extend the time for the cell surface to reach 130 ℃ from 50 s to 180 s under the thermal runaway state of LIB, delaying the triggering and spreading of thermal runaway characteristic temperature.ConclusionsThe CPCM can simultaneously absorb heat in the thermal management range of 20-40 ℃ and the thermal runaway range above 100 ℃, and play an efficient two-stage temperature control role. The research results can provide new ideas for the development of battery thermal management system.