Identifying the Cause of Rupture of Li‐Ion Batteries during Thermal Runaway

Abstract

As the energy density of lithium‐ion cells and batteries increases, controlling the outcomes of thermal runaway becomes more challenging. If the high rate of gas generation during thermal runaway is not adequately vented, commercial cell designs can rupture and explode, presenting serious safety concerns. Here, ultra‐high‐speed synchrotron X‐ray imaging is used at >20 000 frames per second to characterize the venting processes of six different 18650 cell designs undergoing thermal runaway. For the first time, the mechanisms that lead to the most catastrophic type of cell failure, rupture, and explosion are identified and elucidated in detail. The practical application of the technique is highlighted by evaluating a novel 18650 cell design with a second vent at the base, which is shown to avoid the critical stages that lead to rupture. The insights yielded in this study shed new light on battery failure and are expected to guide the development of safer commercial cell designs.

4D imaging of lithium-batteries using correlative neutron and X-ray tomography with a virtual unrolling technique

“…I n recent years, the advancement of X-ray computed tomography (CT) capabilities have facilitated a broadening of our understanding of battery materials and devices, with studies spanning multiple length scales, from nanometre to millimetre, and multiple time scales from kilohertz to microhertz 1 . These studies have collectively provided insight into the relationship between electrode microstructure and performance [2][3][4] , battery architecture, safety [5][6][7][8] and new battery materials [9][10][11] .…”

Oropharyngeal Injury From Spontaneous Combustion of a Lithium‐ion Battery: A Case Report

“…This increased pressure can cause the electrolyte components to ignite, resulting in an explosion or fire. 8 The described case here is most suggestive of mechanical damage leading to this reaction.…”

“…The heated lithium is vaporized, resulting in gaseous lithium release and subsequent increase in the internal pressure of the battery. This increased pressure can cause the electrolyte components to ignite, resulting in an explosion or fire . The described case here is most suggestive of mechanical damage leading to this reaction.…”

Li-Ion Battery Fire Hazards and Safety Strategies

“…In either design, if the vents are clogged by battery materials during the venting process, the battery pressure will increase and result in an explosion [49]. Additionally, in the 18650 battery, Finegan et al [52] found that not only the clogged vent, but also insufficient gas venting can lead to battery bursting. Some 18650 battery designs include a central mandrel for ensuring that the gas has an escape route.…”

“…Some 18650 battery designs include a central mandrel for ensuring that the gas has an escape route. However, under the gas pressure, even the mandrel can move and puncture the battery cap, thereby becoming a high-speed projectile [52].…”