Commercial type 21700 cells with different cathode materials in high power as well as in high energy versions were acquired with capacities ranging from 3 Ah to 5 Ah. Preliminary analysis and characterization of these cells were done by means of electrochemical impedance spectroscopy (EIS) and capacity measurement. Moreover, analysis of the cathode and anode using inductive coupled plasma optical emission spectroscopy (ICP-OES) confirmed the specific compositions for NMC, NCA and LFP cells, respectively.
 
Thermal runaway behavior was evaluated by two methods, both using Accelerating Rate Calorimetry (ARC). With the Heat-Wait-Seek (HWS) test thermal abuse was studied and exothermal reaction temperature rates were evaluated and compared for different cathode materials and states of charge of 60, 80 and 100%. In addition, nail penetration tests were performed to evaluate the safety during mechanical abuse by puncturing and short-circuiting the cell with a steel nail, accompanied by temperature and video recording.