Failure mechanisms and risk assessment methodologies for lithium-ion batteries: A comprehensive review

Lithium-ion batteries have become a main technology for current energy storage systems, enabling the rapid expansion of electric mobility, portable electronics and numerous other applications, offering several advantages over alternative solutions, such as their high energy density and long service life. However, safety issues limit their broader adoption: the combination of intrinsic degradation mechanisms and severe (“abuse”) operating conditions can trigger a thermal runaway, one of the most dangerous phenomena associated with Li-ion systems, ultimately leading to hazardous events such as fires or explosions. Understanding these pathways is essential for the development of safer battery systems and more effective thermal management strategies. This review aims at providing a comprehensive and structured analysis of the degradation pathways and failure scenarios that affect lithium-ion batteries operation, and of the principal methodologies available for their identification and prevention. This has been accomplished by critically analyzing the results reported by several literature studies focused on the performance degradation mechanisms within Li-ion cells and on the influence of external abuse conditions. These data, which often make up a scattered source of information, have then been compared and reorganized to produce a consistent and structured framework of immediate use for the application of risk assessment methodologies. These latter have been evaluated highlighting their strengths, limitations, and applicability to Li-ion batteries. By bridging electrochemical degradation science and safety engineering practice, the resulting framework offers a practical foundation to enhance the safety, reliability, and predictive assessment of lithium-ion battery systems.