Thermal Runaway Mechanism and Prevention Methods of Lithium-ion Batteries

Abstract

With the development of lithium-ion batteries, it has been found that lithium-ion batteries exhibit advantages such as high energy density and long cycle life. Thus, people began to apply lithium-ion batteries to the invention of electric vehicles. However, in recent years, there have been numerous cases where lithium-ion batteries experience thermal runaway and lead to explosions. Aiming at the thermal runaway problem of lithium-ion batteries, this paper explains the mechanism of thermal runaway in lithium-ion batteries. Subsequently, it proposes corresponding prevention and control strategies: the method involves coating the separator with a ceramic layer to protect it, or using a highly heat-resistant polymer substrate to prepare a composite separator as a replacement for the original separator; optimizing the electrolyte by substituting solid electrolytes, flame-retardant electrolytes, etc. for the original liquid electrolyte, or adopting high-concentration electrolytes or local high-concentration designs to inhibit side reactions; and improving the positive and negative electrodes by using alternative electrode materials, or coating the surface of the positive electrode, or optimizing the electrolyte formula for the negative electrode. Finally, the challenges and prospects for the development of high-safety lithium-ion batteries are presented.