Mitigating Thermal Runaway of Lithium-Ion Batteries

This paper summarizes the mitigation strategies for the thermal runaway of lithium-ion batteries. The mitigation strategies function at the material level, cell level, and system level. A time-sequence map with states and flows that describe the evolution of the physical and/or chemical processes has been proposed to interpret the mechanisms, both at the cell level and at the system level. At the cell level, the time-sequence map helps clarify the relationship between thermal runaway and fire. At the system level, the time-sequence map depicts the relationship between the expected thermal runaway propagation and the undesired fire pathway. Mitigation strategies are fulfilled by cutting off a specific transformation flow between the states in the time sequence map. The abuse conditions that may trigger thermal runaway are also summarized for the complete protection of lithium-ion batteries. This perspective provides directions for guaranteeing the safety of lithium-ion batteries for electrical energy storage applications in the future. [Display omitted] Ensuring safety is the utmost priority in the applications of lithium-ion batteries in electrical energy storage systems. Frequent accidents with unclear failure mechanisms undermine the confidence of the industry in utilizing lithium-ion batteries. Moreover, lithium-ion batteries have a unique failure problem, named “thermal runaway,” of which the mechanism is still unclear. Thermal runaway is associated with chemical reactions, short circuits, smoke, fire, and explosion, making the situation more complicated than we can imagine. The real process that drives the failure hides behind deceptive observations. This perspective proposes mitigation strategies for the thermal runaway problem of lithium-ion batteries. The thermal runaway mechanism has been investigated using a time sequence map to the best of our knowledge. The state transition in the time sequence map clearly interprets the underlying mechanisms for all kinds of observations in thermal runaway tests. Effective mitigation strategies have been proposed based on the conscious understanding of the thermal runaway mechanisms. Fortunately, we can properly regulate the thermal runaway hazard and significantly reduce the possibility of battery failure using the proposed control strategies, which can function at the material, cell, or system level in practical situations. How to mitigate thermal runaway of high-energy lithium-ion batteries? This perspectiv