From micro-explosions to full-scale fire: Predicting thermal runaway in ultra-high nickel lithium-ion batteries with layering effect

Lithium-ion batteries (LIBs) are crucial for various applications but are susceptible to thermal runaway (TR), especially as energy densities increase. This study examines TR behavior in LIB components using multi-layer thermochemical analysis. Anode, cathode, and separator layers from 88 % nickel (NCA88) and 91 % nickel (NCA91) cathode-based LIBs were analyzed using Differential Scanning Calorimetry (DSC) under controlled heating rates of 10 °C/min, 15 °C/min, and 20 °C/min. A multi-layer micro-cell configuration was developed to assess layer-dependent thermal interactions. Results indicate that solid electrolyte interphase (SEI) degradation onset varies with both layering and heating rate, occurring as early as 68.9 °C (NCA88, 3-layer, 10 °C/min) and 69.2 °C (NCA91, 2-layer, 10 °C/min). In contrast, for a single-layer system, SEI degradation begins at 97.2 °C (NCA88) and 95.0 °C (NCA91) at 10 °C/min. Cathode degradation initiates between 202.3 °C and 246.6 °C, with peak degradation temperatures reaching 243.9 °C (NCA91, 3-layer, 20 °C/min). Increasing layers led to a broader thermal degradation range, with endset temperatures extending up to 276.8 °C (NCA91, 2-layer, 10 °C/min), indicating improved heat dissipation. These findings highlight the role of layer-wise thermal interactions in influencing TR progression, particularly for NCA91, which exhibits greater thermal stability over NCA88. The study validates a microscopic approach for predicting large-scale LIB failure by using interpolation techniques to estimate TR behaviors in multi-layer battery stacks. The results provide a foundation for enhancing LIB safety through optimized thermal management strategies.