Investigation on the inhibition mechanism of thermal runaway propagation in high-rate cycling lithium-ion pouch cells

With the widespread application of lithium-ion batteries (LIBs) and their high-rate charge and discharge technologies, LIBs face significant safety challenges related to thermal runaway (TR) and its propagation during long-term cycling. The study of thermal runaway propagation (TRP) and the inhibition of its spread is crucial to preventing the further escalation of accidents. In this study, a thermal runaway experimental system was established to systematically evaluate the effectiveness of different barrier materials (stainless steel, aerogel blanket, epoxy board, and nickel foam) and material thicknesses (1 mm and 3 mm) in inhibiting the TRP in high-rate cycling lithium-ion pouch cells. The cycle numbers of 3 C high-rate cycling (30, 50, 70, and 100) were used as variables in the experiment, with key data—such as temperature, voltage, mass loss, and heat transfer—being recorded throughout the process of TRP. The infrared imaging and microscopic characterization techniques were employed to analyze the insulation mechanisms of the materials and the internal changes within the batteries. The results indicated that aerogel blanket performed best in inhibiting TRP, especially at a thickness of 3 mm, where it effectively prevented TR in adjacent cell. In contrast, due to its rapid heat transfer properties, nickel foam demonstrated the poorest inhibition effect. The microscopic analysis further revealed the degradation of the battery electrode and surface chemical composition caused by the 3 C high-rate cycling, offering valuable insights for optimizing battery module design and enhancing the safety of energy storage systems. Additionally, a risk matrix analysis was used to assess the reliability of the inhibition strategies, revealing the effectiveness of this method in evaluating safety measures within the LIBs field.