Comprehensive Hazard Analysis of Failing Automotive Lithium-Ion Batteries in Overtemperature Experiments

Abstract

Lithium-ion batteries (LIBs) are gaining importance in the automotive sector because of the potential of electric vehicles (EVs) to reduce greenhouse gas emissions and air pollution. However, there are serious hazards resulting from failing battery cells leading to exothermic chemical reactions inside the cell, called thermal runaway (TR). Literature of quantifying the failing behavior of modern automotive high capacity cells is rare and focusing on single hazard categories such as heat generation. Thus, the aim of this study is to quantify several hazard relevant parameters of a failing currently used battery cell extracted from a modern mass-produced EV: the temperature response of the cell, the maximum reached cell surface temperature, the amount of produced vent gas, the gas venting rate, the composition of the produced gases including electrolyte vapor and the size and composition of the produced particles at TR. For this purpose, overtemperature experiments with fresh 41 Ah automotive lithium NMC/LMO—graphite pouch cells at different state-of-charge (SOC) 100%, 30% and 0% are performed. The results are valuable for firefighters, battery pack designers, cell recyclers, cell transportation and all who deal with batteries.

Fire boundaries of lithium-ion cell eruption gases caused by thermal runaway

“…Therefore, based on our previous research on the generation reasons (Li et al, 2019a), eruption characteristics (Wang et al, 2019a;Zhang et al, 2020), component identification , ignition sources , and flammability analyses (Li et al, 2019b) of CEGs, we summarize the CEG component identification results of 29 thermal runaway tests conducted in an inert atmosphere, as presented in the literature Somandepalli et al, 2014;Golubkov et al, 2014Golubkov et al, , 2015Lammer et al, 2017;Essl et al, 2020). According to the results, a time sequence diagram of CEG generation is drawn, and the three fire boundaries of CEGs, including c CEG, ignition , c O2, ignition , and T ignition , are analyzed on the basis of thermal ignition theory.…”

“…This study focuses on summarizing the performed works Somandepalli et al, 2014;Golubkov et al, 2014Golubkov et al, , 2015Lammer et al, 2017;Essl et al, 2020) in the last 10 years regarding the identification of CEG in an inert atmosphere because triggered thermal runaway in an inert atmosphere avoids chemical changes as much as possible after the CEG is ejected from the cell.…”

“…Table 1 shows equipment used in the summarized works Somandepalli et al, 2014;Golubkov et al, 2014Golubkov et al, , 2015Lammer et al, 2017;Essl et al, 2020) and the types of gases detected. The used instruments mainly included gas chromatography-mass spectrometers (GC-MSs), gas chromatographers (GCs), thermal conductivity detectors (TCGs), ion chromatographs (ICs), and Fourier transform infrared spectrometers (FTIRs).…”

“…The types of detected gases mainly included hydrogen (H 2 ), oxygen (O 2 ), nitrogen (N 2 ), carbon monoxide (CO), carbon dioxide (CO 2 ), methane (CH 4 ), ethyne (C 2 H 2 ), ethylene (C 2 H 4 ), ethane (C 2 H 6 ), and other hydrocarbons. In addition, diethyl carbonate (DEC), methyl ethyl carbonate (EMC), For more information, refer to ; Somandepalli et al (2014); Golubkov et al (2015); Golubkov et al (2014); Lammer et al (2017); and Essl et al (2020).…”

“…Figure 1 shows the main CEG components detected in the summarized works Somandepalli et al, 2014;Golubkov et al, 2014Golubkov et al, , 2015Lammer et al, 2017;Essl et al, 2020), which were H 2 , CO 2 , CO, CH 4 , C 2 H 4 , and C 2 H 6 . In addition, the components included electrolyte vapor, HF, and other gases.…”