In the past five years, there have been numerous cases of Li-ion battery fires and explosions, resulting in property damage and bodily injuries. This paper discusses the thermal runaway mechanism and presents various thermal runaway mitigation approaches, including separators, flame retardants, and safety vents. The paper then overviews measures for extinguishing fires, and concludes with a set of recommendations for future research and development.

One of the root causes of lithium battery failure is lithium dendrite formation. Dendrites can result in internal short circuits and ultimately thermal runaway, fires, and explosions. Unfortunately, it has been difficult to study dendrites due to an inability to conduct in-situ observations. This paper presents an in-situ observation approach, consisting of an optically transparent lithium battery cell to observe dendrite growth evolution while concurrently monitoring the electrical characteristics of the cell under various current densities.

18650 Lithium-ion batteries are wildly used as power sources for portable electronics because of the standardized format and economical manufacturing cost. However, commercial 18650 cells come in various designs due to the implementation of different protection devices. The current interrupt device and top vent are mandatory protection devices for all commercial 18650 Li-ion batteries. In contrast, the positive temperature coefficient thermistor, bottom vent, and protection circuit are optional protection devices that can be non-installed, installed separately, or combined in commercial 18650 batteries. Four representative commercial 18650 Li-ion batteries were disassembled and compared in terms of the similarities and differences of the protection devices. This paper overviews the working mechanism, advantages, and drawbacks of each protection device. Recommendations on battery selection and potential future trends are then provided.

Electric vehicles (EV) are considered the future of the automobile industry due to their high energy conversion efficiency and environmental friendliness. However, there are safety risks associated with Li-ion batteries, including the potential for fires and explosions. This paper reviews the challenges facing the electric vehicle market regarding the implementation of Li-ion batteries. It then presents two case studies of electric vehicles that experienced safety-related recalls which were not associated with vehicle collisions. For comparison, a history of Li-ion battery safety issues from the same brand in other applications than EV and the company's reactions are provided. The case study and review of issues in other applications show a lack of consideration for customer safety, amplified by the additional risk used in an EV. The paper then explores corrective actions performed and analyzes how the actions will not address the root cause; additionally, contributing to a performance reduction. Recommended corrective actions for future implementation of EV batteries are provided.