“Accepted fire suppression techniques” are behind the times. I have watched videos of lithium fires and their “suppression.” It takes a long time and seems to be effective only when the lithium is all consumed. I watched another vid demonstrating how the lithium foil in a flashlight battery when dipped into water begins to burn furiously.
Apples and oranges. Li-ion batteries do not have lithium metal.
Water is the accepted fire suppression medium.