Investigating thermal runaway propagation characteristics and configuration optimization of the hybrid lithium-ion battery packs

Abstract

Thermal runaway (TR) and its propagation (TRP) in lithium-ion batteries are critical safety concerns. The emergence of hybrid battery packs, combining different battery types (referred to as AB batteries), has gained significant attention as a potential solution to enhance battery safety. However, there is a lack of evaluation regarding the TRP characteristics of these configurations. In this study, various AB battery configurations, incorporating NCM 811 and LFP batteries, are examined through simulations and experiments to investigate their TRP behavior. The findings reveal that: (1) A well-designed AB battery configuration can effectively suppress TR, achieving a balance between high energy density and safety. The high TR trigger temperature and specific heat capacity of LFP batteries play a vital role in impeding TRP. (2) The 8L8L battery configuration successfully suppresses TRP, while the 88L88 configuration requires the addition of heat-insulating sheets for effective TRP suppression. (3) Increasing the number of LFP batteries proves to be an effective approach in preventing TRP. For instance, configurations such as 88LL88 and 888888LL888888 demonstrate no occurrence of TRP. The study concludes by summarizing the TRP characteristics of different AB battery configurations, offering valuable insights for the design of high-safety battery packs.