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

Abstract

Mechanical abuse of lithium-ion batteries is widely used during testing to induce thermal runaway, characterize associated risks, and expose cell and module vulnerabilities. However, the repeatability of puncture or 'nail penetration' tests is a key issue as there is often a high degree of variability in the resulting thermal runaway process. In this work, the failure mechanisms of 18650 cells punctured at different locations and orientations are characterized with respect to their internal structural degradation, and both their internal and surface temperature, all of which are monitored in real time. The initiation and propagation of thermal runaway is visualized via high-speed synchrotron X-ray radiography at 2000 frames per second, and the surface and internal temperatures are recorded via infrared imaging and a thermocouple embedded in the tip of the penetrating nail, respectively. The influence of the nail, as well as how and where it penetrates the cell, on the initiation and propagation of thermal runaway is described and the suitability of this test method for representing in-field failures is discussed.

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] . While the majority of these studies have utilised X-ray CT, there is growing interest in the application of neutron imaging for battery applications; the complementarities of X-ray and neutron imaging, which are sensitive to electron and nuclear density, respectively, provide significant opportunities for correlative studies.…”

Lithium-Ion Capacitor Safety Testing for Commercial Application

“…The heat by entropy change is relatively small compared to heat from resistive heating. The internal temperature of the LIC may be higher than the measured surface temperature because the heating begins inside the cell due to exothermic reaction before conducting outwards through the electrode layers towards the outer surface [17,49]. However, the present study accounts for the external surface temperature only.…”

“…The simulation model shows the capability of estimating the start time of thermal runaway. The internal temperature and structural degradation of the lithium-ion cell was investigated [17] under a nail penetration test with different penetration position for lithium ion cells, where they found out that internal temperature is higher than the surface temperature. The variation between the inner temperature and surface temperature of a supercapacitor was investigated [10] with three dimensional symmetric thermal model based on the heating rate measured during cycling [9] The modeling of increased temperature effect was studied in relation to the charge-discharge current of the supercapacitor [18] which shows that the temperature response is dependent on the current applied.…”

New Insights into Nail Penetration of Li‐Ion Batteries: Effects of Heterogeneous Contact Resistance

“…studied different electrochemical behaviors of internal short circuit using a highly reproducible mechanical penetration method . Various simulations were conducted to investigate thermal behaviors of batteries under nailing . These studies indicate that the heat generation is localized at the contact between a nail and battery electrodes, and the electronic contact resistance ( R c ) at nail/electrode interface is a dominant factor for the magnitude of local heat generation and the maximum temperature increase, which directly affects whether thermal runaway and explosion occur or not .…”