Combination of Phase Change Composite Material and Liquid-Cooled Plate Prevents Thermal Runaway Propagation of High-Specific-Energy Battery  
Weigao Ji  
National Engineering Research Center of Electric Vehicles, Beijing Institute of Technology, Beijing 100081, China; [EMAIL_ADDRESS] (W.J. ); [EMAIL_ADDRESS] (Y.D. ); [EMAIL_ADDRESS] (Y.Y. ); [EMAIL_ADDRESS] (X.Z.) Yongchuo  
National Engineering Research Center of Electric Vehicles, Beijing Institute of Technology, Beijing 100081, China; [EMAIL_ADDRESS]  
thermal runaway (TR) in single LIBs, leading to a cascading TR propagation with a range of hazardous consequences including swelling, fires, and even explosions [5; 6; 7]. Once a fire accident occurs, the harm caused by this model is significantly higher than that of models equipped with lithium-ion iron phosphate batteries. Therefore, improving the safety performance of cells and reducing the risk of heat spread between cells are the keys to reducing the harm caused by such accidents. By strengthening the fire isolation measures inside the battery system and optimizing the cooling technology, the triggering and spreading process of TR can be effectively delayed; then, the open flame can be effectively suppressed to prevent an explosion [8]. At the present stage, the strong randomness and complexity of the TR trigger determine the inevitability of a TR accident; thus, the delay scheme to prevent TR expansion is very important. [PERSON] et al. [9] proposed the use of flame-retardant phase change materials and low thermal conductivity materials to delay the TR expansion of LIBs. The TR tests on battery modules demonstrate that the materials between batteries can efficiently inhibit the spread of TR, maintaining the maximum external temperature of the neighboring battery below 182.6 \({}^{\circ}\)C. [PERSON] et al. [10] confirmed that aerogel felt with flame-retarded phase change material could effectively delay the TR expansion of LIBs. [PERSON] et al. [11] used composite phase change materials to block the TR expansion between 2.85 Ah 18650 cells induced by needle puncture. [PERSON] et al. [12] used aramid honeycomb and hydrogel materials to develop a thermal insulation layer that could be placed between individual batteries; this layer blocked the TR propagation between 37 Ah and NCM111 LIBs triggered by needle puncture. In previous studies, researchers also developed flexible ceramic insulation materials [13], flame-retardant phase change composite materials [14], hydrogel composite materials [15], and other intelligent barrier materials; these materials inhibit or block the TR between different types of lithium-ion batteries by functioning as thermal insulation barrier materials. In addition, the researchers also studied the methods of delaying TR propagation from the perspective of cooling and fire [16; 17; 18] extinguishing, which involved foam [17], fine water mist [19], liquid nitrogen [20],difluorodichloroomethane [21; 22], perfluorohex [23], anone, heptafluoropropane, dry ice [22], and other fire extinguishing agents. These agents were analyzed to determine their fire extinguishing effects on the battery fire and the harm of the material itself to the environment, and certain research results were obtained. However, at present, there is no effective solution to the problem of the TR propagation of high-specific-energy, pouch batteries, such as ternary LIBs; therefore, this study carried out TR research on ternary LIB monomers, modules, and vehicles and obtained the law of TR and its spread. Furthermore, this study explored the passive safety protection method of TR at the battery module level and developed a new phase change composite material. The phase change composite material is based on ceramic nanofiber and is combined with the phase change material using adsorption; it demonstrates excellent heat absorption and heat insulation performance. The material and the liquid cooling plate jointly block the TR propagation, forming a three-level TR timing protection method: heat absorption-conduction-insulation.