3. Thermal Runaway: Causes and Consequences on Cell Level

Lithium-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 lithium-ion batteries with the format 18650. The lithium-ion batteries were deliberately driven into thermal runaway by overheating under controlled conditions. Cell temperatures up to 850 \(^\circ \)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 lithium-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\(_2\).