Analysis on Thermal Runaway Propagation Characteristics and Efficacy of Water Sprinkler System in Shelf Storage of 46120 Ternary Lithium Batteries

Taking the 46120 cylindrical ternary lithium-ion battery as the research object, A full-scale experimental setup with 512 cells was designed to evaluate TR behavior under varying conditions, including TR initiation positions (upper tray edge, lower tray edge, lower tray center), sprinkler arrangements (top-spray, side-spray), and shelf layouts (double-layer, single-layer). The experimental results show that the TR propagation is highly dependent on cell location, and under the same case, the vertical propagation speed (7.7×10 ^− 5 m/s) is significantly higher than the horizontal(5.5×10 ^− 5 m/s). In different sprinkler layout configuration, the top-spray sprinkler arrangement has suppression efficiency with 1-seconds response time, outperforming side-spray sprinkler, which failed to trigger sprinkler response. After the optimization of the shelf layout, the sprinkler trigger time is shortened by 89.8% and 97.6% for edge and center TR positions, respectively, while the efficiency of the sprinkler system is improved by 99.6% and 95.2%. This study provides critical data for optimizing fire protection systems in lithium-ion battery storage facilities, and has reference significance for the storage safety of lithium-ion batteries.