Thermal-runaway experiments on consumer Li-ion batteries with metal-oxide and olivin-type cathodes

Abstract

Li-ion batteries play an ever-increasing role in our daily life. Therefore, it is important to understand the potential risks involved with these devices. In this work we demonstrate the thermal runaway characteristics of three types of commercially available Li-ion batteries with the format 18650. The Li-ion batteries were deliberately driven into thermal runaway by overheating under controlled conditions. Cell temperatures up to 850 C and a gas release of up to 0.27 mol were measured. The main gas components were quantified with gas-chromatography. The safety of Li-ion batteries is determined by their composition, size, energy content, design and quality. This work investigated the influence of different cathode-material chemistry on the safety of commercial graphite-based 18650 cells. The active cathode materials of the three tested cell types were (a) LiFePO 4 , (b) Li(Ni 0.45 Mn 0.45 Co 0.10)O 2 and (c) a blend of LiCoO 2 and Li(Ni 0.50 Mn 0.25 Co 0.25)O 2 .

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

“…When a critical temperature is exceeded locally, and if there is a sufficient amount of electrolyte, a series of exothermic reactions initiate and propagate throughout the cell in a process known as 'thermal runaway'. [1][2][3][4][5][6] In-field puncture-induced failures incur a high degree of variability, which arises from difficulties in controlling parameters such as the internal architecture of the cell, the size, shape, electrical and thermal properties of the puncturing object, as well as the depth and rate at which the cell is punctured. When attempting to replicate a scenario in which a cell undergoes an internal short circuit, the nail penetration test is unsuitable due to it being inherently intrusive, spreading the short circuit across a large area and multiple layers, and introducing a heat sink at the region of initiation.…”

Experimental Analysis of Thermal Runaway in 18650 Cylindrical Li-Ion Cells Using an Accelerating Rate Calorimeter

“…Thus, the amount of gas produced during thermal runaway is (88.53-12.05) mmol, which is 76.48 mmol. A similar procedure was described by Golubkov et al [12] and the amount of gas produced was calculated from the measured external pressure. The cell with the LMO cathode released 76.5 mmol gas during thermal runaway.…”

“…The much lower maximum temperature rate of LFP can not only be attributed to the lower capacity, but also to the much higher thermal stability of this nanoscale material. A similar procedure was described by Golubkov et al [12] and the amount of gas produced was calculated from the measured external pressure. The cell with the LMO cathode released 76.5 mmol gas during thermal runaway.…”

“…After cooling, which is not shown here, the pressure fell below 10 bar again, which is the upper limit for the validity of the ideal gas law. Thus, according to Golubkov et al [12], the ideal gas law equation can be used in order to calculate the amount of gas produced:…”

Influence of aging on the heat and gas emissions from commercial lithium ion cells in case of thermal failure

“…Our group compared the heat and gas emissions of commercial cells of the cylindrical 18650 format in previous studies [9,10,36]. In this work, the tested cells comprise pristine devices as well as cells artificially fast-aged by cycling and cells aged by storing them at 60 °C.…”