A Thermal Runaway Protection Strategy for Prismatic Lithium-Ion Battery Modules Based on Phase Change and Thermal Decomposition of Sodium Acetate Trihydrate

With the rapid development of battery energy storage technology, the issue of thermal runaway (TR) in lithium-ion batteries has become a key challenge restricting their safe application. This study presents an innovative protection strategy that integrates liquid cooling with sodium acetate trihydrate (SAT)-based composite phase change materials (CPCM) to mitigate TR and its propagation in prismatic battery modules. Through numerical simulation, this study systematically investigates the TR protection mechanism and optimization pathways for prismatic battery modules. The results indicate that pure SAT exhibits poor latent heat performance due to its low thermal conductivity. In contrast, the incorporation of expanded graphite (EG) significantly enhances thermal conductivity and improves the overall latent heat performance. Compared to traditional paraffin-expanded graphite (PA-EG), SAT-EG, with a latent heat 4.8 times higher than that of PA-EG, demonstrates more than six times the effectiveness in delaying thermal runaway propagation (TRP). When combined with liquid cooling, the TR protection effect is further enhanced, and TR will not be triggered when the initial abnormal heat generation rate is relatively low. Even if an abnormal battery experiences TR, its propagation will be prevented when the thickness of the SAT-EG exceeds 12 mm. Ambient temperature influences both the peak temperature and the timing of its occurrence in the battery module. Among the different liquid cooling layouts, the combined bottom and side cooling scheme exhibits superior performance compared to the standalone schemes.