It is common practice to submerge EVs in water for several days in Germany, too. Remember that there is no elemental lithium (which would react with water) in batteries. As with every fire, the goal is to cool down the battery, so the fire doesn’t have enough energy to burn further. Unfortunately I only found German sources to back this up.
This is my googled understanding, take with a grain of salt:
Batteries contain of lots of individual cells. If you short-circuit one cell, you generate lots of energy (from the short-circuit), and start a chemical reaction (fire) that does produce its own oxygen. Once that cell has lost all its charge, the reaction would stop, but until then the fire has compromised neighboring cells, which start the process all over again.
Water won’t stop the first broken cell from discharging, but it can bring the battery down to a temperature where the fire is too cold to sustain itself. It contains the damage to the cells that are affected already and prevents more cells from igniting. This is how you stop a battery fire.
The car gets put into a tank for several days to allow the broken battery cells to discharge safely, without overheating and causing another fire.
It is common practice to submerge EVs in water for several days in Germany, too. Remember that there is no elemental lithium (which would react with water) in batteries. As with every fire, the goal is to cool down the battery, so the fire doesn’t have enough energy to burn further. Unfortunately I only found German sources to back this up.
Can batteries be extinguished? I thought the whole point was they were self-fueling and burn at least until the charge energy is gone.
This is my googled understanding, take with a grain of salt:
Batteries contain of lots of individual cells. If you short-circuit one cell, you generate lots of energy (from the short-circuit), and start a chemical reaction (fire) that does produce its own oxygen. Once that cell has lost all its charge, the reaction would stop, but until then the fire has compromised neighboring cells, which start the process all over again.
Water won’t stop the first broken cell from discharging, but it can bring the battery down to a temperature where the fire is too cold to sustain itself. It contains the damage to the cells that are affected already and prevents more cells from igniting. This is how you stop a battery fire.
The car gets put into a tank for several days to allow the broken battery cells to discharge safely, without overheating and causing another fire.
Interesting. Thank you.