The Energy Storage System (ESS) market is rapidly expanding as global environmental policies are pushing for renewable energy with an increasing momentum. However, due to the thermal runaway phenomenon specific to lithium-ion batteries (LIBs), ESSs are prone to catching fire, and initial suppression is difficult under current countermeasures. In this study, we introduce a liquid-immersed battery (LImB) ESS, in which the battery cells are fully submerged in a liquid agent. The full-immersion structure of the ESS with the particular thermal properties of the liquid agent blocks fire propagation. Moreover, the immersion system improves thermal management efficiency during normal operation. These enhanced thermal management performances of the LImB ESS were validated under various conditions at an independent energy station. These findings suggest that the liquid-immersed battery system paves the way for safe and efficient ESS operation by enhancing thermal management and fire suppression.
Keywords: lithium-ion battery safety; energy storage systems; thermal runaway; fire suppression; battery thermal management system