Thermal runaway propagation in large format lithium ion battery modules under inclined ceilings

Abstract

Currently, the horizontal ceiling structure is widely adopted in large format battery systems. Thus systematically investigating the thermal runaway (TR) propagation behaviors features of large format lithium ion battery modules under different inclined ceilings is of importance for the safety design and protection of battery systems. This work focuses on the experimental phenomenon elucidation and theoretical analysis of the single cell TR and its propagation. Firstly, a single cell test is carried out to investigate the TR behavior features of target battery. Then, four sets of TR propagation tests with different ceiling angles (0°, 10°, 30°, 90°) are performed to explore the effect of inclined ceiling angle on TR propagation. Besides, a set of 0° ceiling angle experiment with fireproof barriers is conducted to study the blocking effect of barriers. Results show that a larger ceiling angle provides a better heat dissipation condition for modules, and the threshold value of ceiling angle at which TR stops propagating is between 10 and 30°. The barriers cannot block the TR propagation but great delay and weaken the propagation process. This study helps to enhance the insight of TR propagation behaviors and provides valuable guidance for the relative researchers and engineers.