Abstract: This paper constructs a semi-open indoor building scenario and conducts full-scale fire tests on new energy vehicle charging bays under the action of conventional building fire sprinkler systems and a new underfloor sprinkler system. By collecting ambient temperature and combustible gas data, the study deeply analyzes the influence of different fire suppression systems on the thermal runaway development characteristics of lithium-ion battery packs and the resulting fire control effectiveness. The results show that the conventional overhead sprinkler system fails to suppress the thermal runaway of the battery pack or the subsequent vehicle combustion process. In contrast, the new underfloor sprinkler system can rapidly detect thermal runaway in new energy vehicles and effectively mitigate and control the thermal runaway process of the battery pack. Based on the experimental process and results, engineering application recommendations for the new underfloor sprinkler technology are proposed. The research findings provide experimental support and design references for the early identification and engineering application of control technologies for thermal runaway characteristics of lithium-ion battery packs in building-integrated new energy vehicle charging lots.

Key words: indoor charging parking spaces for NEV, thermal runaway of lithium-ion batteries, conventional fire top sprinkler, new underspray technology, full-scale fire test