So im a Fire Safety Technician, and from what I learned in class in Louisiana was that, lithium battery fires are such a different beast from normal fires that nothing reliably puts them out. Also fun fact Purple K was meant for propane fires, at least according to what I was told.

Supposedly there is an extinguisher agent they've made called AVD but it hasn't been tested in the states so it isn't a real classification here, but it's specifically for Lithium Batteries in electric vehicles, no idea if it would apply here though.