Analysis of Thermal and Heat-Release Characteristics of Thermal Runaway with Increasing Number of Lithium-Ion Pouch Cells

With the increasing use of lithium-ion batteries (LIBs), the need for an effective response to thermal runaway fires has become increasingly important. To evaluate the performance of fire extinguishers specifically designed for battery fires, the scale and thermal behavior of thermal runaway fire sources must be quantified. In this study, the thermal runaway characteristics of lithium-ion pouch cells were investigated as a function of cell number. Test specimens consisting of 1-10 pouch cells were prepared, and thermal runaway was induced using a heating film. The intercell temperature, heat release rate, and total heat release (THR) were measured. The peak heat-release rate generally increased with the number of cells, although variations were observed among the test conditions, and the coefficient of determination from the linear regression analysis was 0.7494. The THR tended to increase relatively consistently with the number of cells, with a coefficient of determination of 0.9573. However, because each cell number condition was tested only once, the regression results should be interpreted as representing the specific experimental conditions rather than as generalized statistical relationships. The study results can serve as fundamental data for examining fire sources and performance evaluation conditions for battery-specific fire extinguishers and extinguishing agents requiring further verification through repeated testing.