In situ neutron imaging of lithium-ion batteries during heating to thermal runaway

加熱リチウムイオン電池内部の中性子その場観察

野崎 洋*; 近藤 広規*; 篠原 武尚   ; 瀬戸山 大吾*; 松本 吉弘*; 佐々木 厳*; 伊勢川 和久*; 林田 洋寿*

Nozaki, Hiroshi*; Kondo, Hiroki*; Shinohara, Takenao; Setoyama, Daigo*; Matsumoto, Yoshihiro*; Sasaki, Tsuyoshi*; Isegawa, Kazuhisa*; Hayashida, Hirotoshi*

Lithium ion batteries (LIBs) have become essential components that power most current technologies, thus making various safety evaluations necessary to ensure their safe use. Heating tests remain the most prominent source of safety issues. However, information on the phenomena occurring inside batteries during heating has remained inaccessible. In this study, we demonstrate the first in situ neutron imaging method to observe the internal structural deformation of LIBs during heating. We developed an airtight Al chamber specially designed to prevent radioactive contamination during in situ neutron imaging. We successfully observed the liquid electrolyte fluctuation inside a battery sample and the deformation of the protective plastic film upon heating up to thermal runaway.