Safety Assessment of Large‐Format Quasi‐Solid‐State Lithium‐Ion Batteries

Abstract Quasi‐solid‐state batteries (QSSBs) are currently a promising energy storage technology toward high manufacturability and lower internal resistance compared to all‐solid‐state batteries. However, the safety performance of QSSBs under various abuse conditions, particularly concerning combustion and explosion, remains inadequately characterized. Herein, the thermal runaway (TR) behavior of 32 Ah QSSBs is evaluated with an energy density of 300 Wh kg −1 under thermal and electrical abuse. Accelerating rate calorimeter tests reveal that the QSSBs exhibit a lower peak temperature rise rate (114 °C s −1 ) and a longer self‐heating duration (1513 min) compared to conventional LiNi 0.8 Co 0.1 Mn 0.1 O 2 ‐based lithium‐ion batteries (LIBs). Fast‐charging tests under high preloads show that TR intensity increases with the charging rate, accompanied by violent gas release and flame ejection. Higher preload delays the initiation of TR but intensifies the associated hazards. Gas analysis shows lower gas production (0.76 L Ah −1 ) and narrower explosion limits than most liquid‐electrolyte LIBs. This study highlights the milder thermal and gas production behavior of QSSBs, providing valuable insights for the advancement of high‐specific‐energy storage systems, such as long‐range electric vehicles and power sources for aircraft.