Energy Storage Science and Technology ›› 2019, Vol. 8 ›› Issue (6): 1076-1081.doi: 10.12028/j.issn.2095-4239.2019.0057

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Venting process of lithium-ion power battery during thermal runaway under medium state of charge

WANG Hewu, ZHANG Yajun, LI Cheng, LI Weifeng, OUYANG Minggao   

  1. State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
  • Received:2019-04-16 Revised:2019-04-23 Online:2019-11-01 Published:2019-04-23

Abstract: An electric vehicles used commercial prismatic battery cell with lithium nickel manganese oxide cathode was selected to research the venting process of the products released during thermal runaway. The test was carried out in a sealed chamber with nitrogen as an inert protective environment to avoid combustion, and a high-speed photography was adopted to capture the rapid venting process. The sudden change of the detection pressure indicated that two intense injections occurred during the venting process under medium state of charge, and separately resulted in a sudden decrease and a rapid increase of the temperature in the jet region. With the aid of the auxiliary light source, high-speed images of the first venting evolution of the products caused by thermal runaway were captured. Further analysis revealed that the venting process experiences an initial strip and cone eruption first, followed by a longer period of amorphous eruption, and then a later inverted conical eruption. At the same time, the characteristics of gas-liquid-solid three-phase coexistence were also observed in the images.

Key words: lithium-ion battery, thermal runaway, venting, high-speed photography

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