A review of processes and mechanisms driving structural and mechanical evolution in lithium-ion batteries

Performance degradation in lithium-ion batteries (LIBs) is often accompanied by structural and mechanical changes that pose safety risks, including internal pressure buildup, deformation, fire hazards and enclosure rupture. Understanding and controlling these structural and mechanical changes is vital to maintaining battery safety and reliability, particularly as LIBs are central to advancing global electrification and achieving net-zero emissions targets. This review systematically examines the processes responsible for such structural evolution in LIBs, distinguishing between reversible mechanical expansion caused by electrode expansion and irreversible deformation due to gas generation and interfacial degradation. The influence of temperature extremes and cycling protocols on the accumulation of mechanical stress is studied. Key mitigation strategies, including material optimization, design improvements, and operational protocols, are discussed to address these challenges. This review contributes to the advancement of battery safety for applications in electric vehicles and renewable energy systems, while also highlighting areas where further research is needed.