In-operando high-speed tomography of lithium-ion batteries during thermal runaway

Abstract

Prevention and mitigation of thermal runaway presents one of the greatest challenges for the safe operation of lithium-ion batteries. Here, we demonstrate for the first time the application of high-speed synchrotron X-ray computed tomography and radiography, in conjunction with thermal imaging, to track the evolution of internal structural damage and thermal behaviour during initiation and propagation of thermal runaway in lithium-ion batteries. This diagnostic approach is applied to commercial lithium-ion batteries (LG 18650 NMC cells), yielding insights into key degradation modes including gas-induced delamination, electrode layer collapse and propagation of structural degradation. It is envisaged that the use of these techniques will lead to major improvements in the design of Li-ion batteries and their safety features.

Tracking Internal Temperature and Structural Dynamics during Nail Penetration of Lithium-Ion Cells

“…Such high internal temperatures during thermal runaway were previously inferred for similar cells 17 by observing melting of copper current collectors (melting point of copper 1085…”

“…This suggests that gases generated within the electrode assembly in the bottom portion of the cell initially flowed toward the vacant base of the casing and thereafter changed direction toward the vent, a tortuous path for pressure relief. This buildup of pressure at the base of the cell and consequent doming is not unique to mechanical abuse scenarios; similar shifts of the electrode assembly have also been observed under thermal abuse conditions 8,17 and are expected to be the primary cause of cell rupture and ejection of their contents.…”

“…11,12,15,16 To understand the variation of failure mechanisms in response to different abuse conditions, a spatio-temporal description of thermal runaway resulting from each scenario is needed. High-speed X-ray computed tomography (CT) and radiography have been used in previous studies to visualize the internal breakdown and ejection of active materials following thermal runaway induced via thermal abuse, 17 electrical overcharge 18 and internal short-circuiting. 8 Failures induced via intrusive mechanical methods are expected to deviate most significantly from other in-field failures, in particular internal short-circuiting, which nail penetration is sometimes used to simulate.…”

Smart Electrochemical Energy Storage Devices with Self‐Protection and Self‐Adaptation Abilities

“…[67][68][69][70] Two types of techniques have been developed to address the thermal runaway problem. One method is to inhibit heat generation by adopting alternative electrolytes, e.g., polymer gel electrolytes and solid-state electrolytes with low ionic conductivities.…”

Trends and advances in Operando methodology

“…Inside the complex membrane reactors for oxidative coupling of methane (OCM) reaction could be seen through [36] and in another study even a catalyst particle in liquid phase chemistry could be studied [37]. Impressive time-resolution (>1 Hz) was demonstrated in battery research under operando thermal runaway using CT-tomography and radiography combined with thermal imaging [38].…”