Modeling and simulation of thermo-electrochemistry of thermal runaway in lithium-ion batteries

Innovative Early Detection of High-Temperature Abuse of Prismatic Cells and Post-Abuse Degradation Analysis Using Pressure and External Fiber Bragg Grating Sensors

“…However, the irreversible rise of pressure only started after the high-temperature phase at 75 • C (Figure A6). Reaching the onset temperature of the SEI decomposition led to gas emissions that increased exponentially with increasing temperatures due to the decomposition reaction rate (Figure 8) [51]. This was also consistent with the measurable plastic deformation of the rupture disc by the fiber optic sensor system after the high-temperature step in the setup, which was conducted with a balanced distribution of adhesive on both sides of the middle perforation.…”

“…The decomposition of the main component of the SEI can be described by the global reaction form at which the metastable (CH 2 OCO 2 Li) 2 reacts to the stable inorganic Li 2 CO 3 , as expressed in Equation (2) [51]. Furthermore, the reaction was shown to be largely independent of the lithium content of the anode [52].…”

“…At high temperatures, these reactions contribute to an irreversible growth of the stable SEI component (Li 2 CO 3 ), which passivizes the active material and thus increases the cell's resistance, as well as a deactivation of active anode regions [57]. Both the formation (Equation (1)) and the decomposition (Equation (2)) of the SEI layer are exothermic reactions which bind of lithium ions and lead to gas evolution [31,51]. When the emission of gases is compared (Equations ( 1) and ( 2)), it is obvious that significantly more gaseous species are released during the decomposition of the SEI layer, which shows that the measured pressure increase strongly depends on the onset of the decomposition.…”