Size and elemental composition of fine particles from li-ion battery cell explosion

abstract

English

Banning cars with internal combustion engines will dramatically increase the number of electric vehicles containing lithium-ion battery cells. New technology may bring risks in firefighting that are not fully understood yet. One of the main risks is the appearance of a thermal runaway phenomenon. It occurs when the battery cell is under thermal, mechanical, or electrical load. The cause is usually by a failure of the separator by direct connection of cathode and anode. A battery cell in thermal runaway releases heat and smoke and may result in fire and explosion. The smoke contains high volume of toxic gases and fine particles released into the air. Heavy metals in fine particles may be dangerous for the human body when inhaled. In this study cylindrical 18650 lithium-ion battery cells were subjected to controlled heating until thermal runaway occurred. The cathode chemistry of battery cell LGDBHG21865 was NMC and Sony US18650VTC5A was NMC/LMO. The state of charge of battery cells before the experiment was 100 %. The failure of the battery cells led to an explosion caused by the release of flammable electrolytes, followed by a fire. The explosions occurred within an enclosed apparatus to retain the released particles. The inner air circulated through a single filter, to capture particles across a wide size range. The following experiments employed the same battery cells and utilized a cascade impactor Dekati HT-DLPI+ to collect the released particles. The impactor captures particles in 14 stages according to their size from 14 nm to 10 μm. The particle size distribution was assessed gravimetrically. The highest mass of particles was in fraction 252 nm to 377 nm for battery cell LGDBHG21865 and 152 nm to 252 nm for battery cell Sony US18650VTC5A. Each filter containing particles was subsequently analyzed using atomic absorption spectrometry (AAS) to determine the elemental composition of Ni, Mn, Co, Cu, and Al. The sample was atomized using an electrothermal atomizer. Samples of filters with particles were decomposed in aqua regia by microwave digestion system and determined for tested metals by AAS in device ContrAA 800. In all the filters, Nickel or Aluminum had the highest concentration among other elements. In the majority of the 14 stages filters between 4 % and 12 % of mass were detected elements. The rest remains unclear. Single filters contained 25,8 % of detected elements for LGDBHG21865 and 49,0 % for Sony US18650VTC5A. The results obtained from the study will serve to determine the negative impact on the environment and human body and to develop safe ways of firefighting with electric vehicles.

battery, size distribution, particulate matter, AAS, thermal runaway

PREISLER, L.; JONÁŠOVÁ, S.

30. 11. 2023

Vysoké učení technické v Brně, Fakulta chemická

Brno

978-80-214-6204-5

Studentská odborná konference Chemie je život 2023 Sborník abstraktů

první

91

91

1

https://www.fch.vut.cz/vav/konference/sok/vystupy/sbornik-abstraktu-2023-na-web-pdf-p251584