Abstract: For studying the fire safety of electric ships powered by ternary lithium batteries, an experimental platform of lithium battery cabin on a ship was established and a series of largescale fire experiments were performed by simulating the fire scenario in the cabin. Ternary lithium batteries and lithium iron phosphate batteries were taken, and the suppression effectiveness of four types of marine fixed fire-extinguishing systems on their initial fires were compared in terms of fire suppression phenomena, cooling effect and re-ignition interval time. The results showed that pressure water-mist fire-extinguishing system had a good suppression effect on these two kinds of battery fires, and no re-ignition occurred when the water spraying intensity was 5 L/（min · m2）and 10 L/（min · m2）. Carbon dioxide, heptafluoropropane and aerosol fire- extinguishing systems could extinguish these two kinds of battery fires instantly, but the suppression time was limited and there was the potential to re-ignite. Among these three systems, the cooling effect of aerosol was the worst and re- ignition interval was the shortest, followed by carbon dioxide and then heptafluoropropane, and in general ternary lithium battery fires were more difficult to be extinguished than lithium iron phosphate battery fires, with higher re- ignition rate and shorter re- ignition intervals. According to the comparative results, some fire fighting countermeasures were put forward.

Key words:  , electric ships, ternary lithium batteries, lithium iron phosphate batteries, fire extinguishing test, cooling effect, re-ignition