Optimization of fast-charging strategy for LISHEN 4695 cylindrical lithium-ion batteries

Developing fast-charging technology for lithium-ion batteries with high energy density remains a significant and unresolved challenge. Fortunately, the advent of the 46 series large cylindrical batteries featuring an innovative "tabless" design has considerably enhanced the fast-charging capabilities of lithium-ion batteries. This study presents an 18-min fast-charging technology for 4695 large cylindrical batteries, which exhibit an impressive energy density exceeding 280 Wh kg-1 and can endure over 1200 cycles. This capability equates to a driving range of more than 600,000 km, and each charge is a fast one. Through the utilization of charge-discharge tests, three-electrode analysis, and thermodynamic simulations, critical parameters are meticulously evaluated, including the lithium plating boundary based on 10 mV standard lithium plating potential, an optimal operating temperature of 25 degrees C, an appropriate electrolyte injection coefficient of 1.45 g/Ah, and a suitable quick-charge type of 4C-9steps. Additionally, both destructive and non-destructive analyses of fresh and cycled cells reveal that the degradation of anode materials is the primary factor causing the observed performance degradation. The above optimization of fast charging strategy and failure behavior analysis based on 4695 large cylindrical batteries provide significant insights and have crucial implications for the expedited commercialization of 46 series large-format cylindrical batteries.