Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (1): 201-210.doi: 10.19799/j.cnki.2095-4239.2021.0369

• Energy Storage Test: Methods and Evaluation • Previous Articles     Next Articles

Thermal runaway characteristics of LiFePO4 and ternary lithium batteries with external overheating

Hongzhang ZHU1(), Chuanping WU2, Tiannian ZHOU2, Jie DENG1   

  1. 1.Changsha University of Science & Technology, Changsha 410114, Hunan, China
    2.State Key Laboratory of Disaster Prevention & Reduction for Power Grid Transmission and Distribution Equipment (Hunan Electric Power Corporation Disaster Prevention and Reduction Center), Changsha 410007, Hunan, China
  • Received:2021-07-26 Revised:2021-08-16 Online:2022-01-05 Published:2022-01-10
  • Contact: Hongzhang ZHU E-mail:895940611@qq.com

Abstract:

Lithium-ion batteries have been widely used in energy storage and electric vehicles, but there are risks of fire and explosion due to their flammability. This paper studied the thermal runaway characteristics of 40 A·h ternary lithium and 72 A·h LiFePO4 batteries by external overheating at different positions. The experimental results showed that the LiFePO4 battery does not ignite under the external overheating condition, but the ternary lithium battery ignited and sprayed spontaneously. The side heating can enter the thermal runaway faster than the bottom heating. From the heat transfer analysis, the heat conduction per unit heating area required for 40 A·h ternary lithium battery thermal runaway is 1650—3788.76 kJ/m2. The heat conduction per unit heating area of 72 A·h LiFePO4 battery is 3264.84—7856.67 kJ/m2. In addition, the combustion spread characteristics of the battery pack were studied, taking a 720 A·h LiFePO4 battery pack as the research object. The experimental results showed that if the heat source is in place till, after the external ignition, it spreads to the nearby battery and continues to spray. The heat transfer value of 39.7—43 kJ between the adjacent batteries is obtained from the heat transfer analysis. The results of this study can provide theoretical guidance for fire risk assessment of energy storage power stations and lithium battery fire protection.

Key words: lithium-ion batteries, external overheating, thermal runaway, heat transfer analysis, combustion spread characteristics

CLC Number: