Abstract:

Lithium-ion batteries (LIBs) have raised increasing interest due to their high potential for providing efficient energy storage and environmental sustainability. LIBs are currently used not only in portable electronics, such as computers and cell phones, but also for electric or hybrid vehicles, but frequent fires and explosions limit their further and more widespread applications. This is still a very serious problem, as there are fires in electric vehicles almost every week around the world. This review summarizes aspects of LIB safety and discusses the related issues, strategies, and testing standards. Specifically, it begins with a brief introduction to LIB working principles and cell structures, and then provides an overview of the notorious thermal runaway, with an emphasis on the effects of mechanical, electrical, and thermal abuse. The following sections examine strategies for improving cell safety, including approaches through cell chemistry, cooling, and balancing, afterwards describing current safety standards and corresponding tests. The review concludes with insights into potential future developments and the prospects for safer LIBs. The development of temperature-sensitive materials to use inside batteries to prevent localized temperature increases offers an excellent solution to the thermal runaway problem. Another promising heat dissipation approach is to provide internal pathways for rapid heat diffusion. Last, but not least, careful selection of active electrode materials and electrolytes is also essential for reducing heat and gas production, and to protect the electrode interfaces.