Research progress in low-temperature discharge performance of Ni-rich ternary lithium-ion batteries

With the rapid development of the new energy automotive industry, consumers' requirements for the range of electric vehicles have been increasing. The Ni-rich ternary lithium-ion battery has become the most promising power battery in electric vehicles due to its high specific energy, but the battery system still faces the problem of poor performance at low temperature.The research progress on low temperature performance of Ni-rich ternary power battery in recent years was summarized in this review. The influence factors on the low temperature performance of Ni-rich ternary power battery were summarized emphatically. On the one hand, the effects of low temperature performance from thermodynamics were analyzed, including the structural change of the Ni-rich ternary cathode materials and graphite anode materials, electrolytic phase transformation and solvation structure changes, and glass transition of binder. On the other hand, rate controlling step in the low temperature discharge process in the Ni-rich ternary lithium-ion battery was summed up. According to this, main modification measures of low-temperature performance in Ni-rich ternary power battery were summarized. Low temperature electrolyte was designed by optimizing solvents, improving lithium salts and applying new additives. In order to improve the low temperature performance of electrode materials, three methods were mainly employed: substitution, surface modification and smaller material particle size. The remaining shortcomings of the research on low-temperature performance of the battery were summarized, and the research on the low temperature thermodynamic characteristics of batteries is not clear enough. In addition, the research methods for the low temperature kinetic process of batteries are single, and the influence of the reaction sequence in batteries is insufficiently understood.