A comparative investigation of aging effects on thermal runaway behavior of lithium ion batteries

Thermal runaway is a major concern for the large-scale application of lithium-ion batteries. The thermal runaway performance of lithium-ion batteries not only depends on materials and cell design, but also changes with degradation. This paper presents a comparative investigation of the aging effects on the thermal runaway behavior of a large format lithium-ion battery. The batteries are first degraded under four different aging paths. The aging mechanisms are then investigated through post-mortem analysis on the battery at the end of life, by comparing the electrochemical properties, morphology and composition of the fresh and degraded electrodes. The thermal stabilities of the fresh and degraded electrodes are also evaluated using differential scanning calorimetry. Adiabatic thermal runaway tests are performed on the batteries at different states of health using accelerating rate calorimetry to reveal the evolution …