For any kinds of Car, I believe that it is not suitable to use water-based material to eliminate fire. For ICE, fuel cannot stop burning with water, insteadly, leaked oil and fuel gas with steam may make the situation even worse(with hydrogen and oxygen), and cause burning of other material like polymer and paints; For EV, water may cause more short-circuit and hence more heat source, especially on a system that is lossing control of heat, and likely, melting its insulation material. Meanwhile, the pollution caused by corrosive solute may also increasing the damage of electronic system, like damaging the tubes and building structure, or make charging devices in the parking space( which is likely to be right close to EV car. The conductive water may also bring firefighter into danger, in case of the power system doesn't cutoff correctly when fire happens.

Water does have the advantage of being safe, and having a high heat capacity.  You would need tonnes of sand to put out a single car fire .... Water based foams can be most effective on liquid fuels, or dry powders, but the water based foams are easier to get to site, and to clear up afterwards.

Mike. 

Water does have the advantage of being safe, and having a high heat capacity.  You would need tonnes of sand to put out a single car fire .... Water based foams can be most effective on liquid fuels, or dry powders, but the water based foams are easier to get to site, and to clear up afterwards.

Mike.