Analysis and Evaluation on System Safety of Power Battery Pack under Mechanical Loading

Abstract

Power battery packs are complex system wholes. For complex systems, considering only the reliable safety of components does not guarantee the safety of their systems. It is urgently needed to analyze and evaluate the safety of power battery packs from the system level. Using the theory of complex system safety combined with the actual working conditions of electric vehicles, a quantifiable and hierarchical system safety evaluation of power battery pack is proposed based on the whole refinement model. To ensure that the model of the lithium-ion cells is refined, the power battery pack is simulated and analyzed from three common working conditions, such as positive collision, lateral collision and vibration impact, and the key factors affecting the system safety of power battery pack are comprehensively evaluated by the method of hierarchical analysis(AHP) and fuzzy comprehensive evaluation (FCE). The results show that the system safety of power battery pack has low level, and safety performance is poor. The method can provide reference for the forward structure design and system safety improvement of power battery pack.