Just to be clear. Is this a battery in one of their vehicles or a stand alone battery for storing electrical energy?
Bank of batteries in a stationary rack.
Neither.
This isn’t an EV car battery, nor an individual charging station.
This is outside the codes and standards.
The project consists of 256 Tesla MEGAPACK BESS units on 33 concrete slabs for a total of 730MWh capacity.
The are Lithium Ion batteries, which once they go into thermal runaway, cannot be extinguished. It is a solid chemistry exothermic reaction, with flame temps up to 1500deg C. (Melts most stainless steels.)
Outgassing can generate 5 cuft of toxic and highly toxic flammable heavier than air gas per battery cell (say a 3.0 -4.2V x 10Ah battery cell like in your laptop or cellphone).
In these quantities, both the HAZMAT cleanup and evacuation to upwind areas is best policy.
Only thing firefighters can do is use water to disperse heat from adjacent facilities.
See my previous link to the McMicken BESS incident in 2019 outside Phoenix.
Buzzword is NFPA 855, which only allows up to 600kWh / BESS charging system. The MEGAPACK is about 3MW / BESS.
Think of the Hindenburg on steroids.
https://freerepublic.com/focus/f-chat/4093555/posts