Safety design of aviation propulsion lithium-ion battery systems based on thermal runaway explosion index

With the development of society and increasing changes in energy demands, safety issues concerning lithium-ion batteries in applications such as electric aircraft have garnered significant attention. To investigate the influence of aviation propulsion lithium-ion battery system design on safety performance, this research introduces the concept of the Thermal Runaway Explosion Index and applies it to the quantitative assessment of lithium-ion battery system safety design. Through experimental and theoretical analyses, utilizing self-built modules for lithium-ion battery thermal runaway, gas explosion characteristics testing, and thermal runaway containment testing, a quantitative assessment was conducted on the inherent safety, operational safety, and protective safety of the lithium-ion battery system. The results demonstrate that protective design plays a critical role in reducing the thermal runaway explosion index. Specifically, the protective effect achieved by applying a fireproof coating is superior to that obtained by increasing the thickness of the top plate. Moreover, the E85S15B3 coating exhibits the optimal performance in reducing both temperature and weight. Following correction with 1 mm thick E85S15B3 coating protection, the thermal runaway explosion index is 0.0942. Compared to the scenario without a protective top plate, the maximum temperature drops by 55.80%, and the weight of the battery top plate can be reduced by 36.59% under equivalent volume conditions. The conclusion of this research provides a theoretical basis and practical guidance for the hazard assessment and system safety design of aviation lithium-ion battery systems.