Failure mechanism of 18650 Li-ion batteries induced by the heating accumulation of tab

Abstract

Failure analysis of lithium-ion batteries is an effective way to discovery the defects and improve the reliability of batteries. Nevertheless, defects of LIBs in manufacturing process leading to failure are easily ignored in the scientific researches. This work investigates the failure mechanism of the failed 18650 Li-ion batteries pack. The combination of non-destructive test and micro-zone characterizations rapidly locate the failure position of anode tab. Results show that the poor welding technology of anode tab induces the heating accumulation. Long-term overheating causes the peeling of active materials and the close-packed of separator pores, which finally leads to the thermal runaway of the battery.