Characteristics of residue of ternary Li-ion traction battery induced by internal short-circuit
The typical characteristics of the residue are investigated by triggering internal short-circuit thermal runaway through nail penetration to LiNi0.8Co0.1Mn0.1O2(NCM811) Li-ion traction battery.During the experiment,the surface temperature and voltage data of the battery are monitored and the experimental phenomena are recorded.The 3D scanning imaging of the battery before and after the nail penetration is performed by industrial computed tomography (CT),the microstructure and morphology of the electrode residue after thermal runaway are analyzed by XRD,SEM and metallographic microscope.After thermal runaway,the cell of the battery is deformed and torn,the direction of the cell deformation and extrusion points to the internal short-circuit initiation point.In the XRD pattern of the residue material at the initiation site of the internal short-circuit,typical composite phase diffraction peak appears.The residual copper foil at the initiation point of the internal short-circuit presents fine dendrites and equiaxial crystals.The above characteristics of the residue can be used as the basis for locating the internal short-circuit trigger point.