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[Ranga]

In electric motorcycles and cars, what safety equipment is in place (if any) to prevent arcing, short-circuiting or electrocution in the event of a crash that destroys the batteries? Obviously nothing will prevent this if the batteries are thrown from the vehicle, but in a conventional accident what keeps the vehicle safe to handle?

[Doug S]

That seems like a bit of a loaded question to me. You can't ask an engineer to design a product that's safe when it gets destroyed. In the final analysis, it's just not really possible.

First, anything that stores energy (a battery, a tankful of gasoline, etc.) can under some set of conditions release that energy way faster than intended. ICE vehicles and EVs can both catch on fire and "catastrophically deconstruct" in pretty dramatic fashion. Okay, you may say that there is a higher risk of electrocution for first responders trying to sort out an EV collision, but there's a lot lower risk of severe burns (fewer very hot parts) as well. And while we all know that pooled liquid gasoline doesn't actually burn very well, with lots of liquid gasoline lying around, in and on hot engine parts, there is a finite risk that somewhere in the air, the gasoline vapor will fall in between the lower explosive limit and upper explosive limit, and you'll have an explosion -- it does happen. First responders try to be very careful to avoid creating sparks whenever possible.

I'd say look at the track records. I don't know if there have really been enough incidents for a statistically valid comparison, but it certainly doesn't seem that EVs are significantly riskier to handle after an accident than ICEs, if at all. I know first responders are very concerned about it, but I think that's largely out of unfamiliarity and lack of guidelines, not any real elevated risk.

[hubert]

The very few cases of EV crashes with fire, or even EVs getting on fire without a crash (Tesla...) have been intensely buzzed by worldwide media, creating a kinda "feling" that EV's are very prone to burning. Of course, the thousands of ICE cars burning everyday are such a routine that nobody cares. Except firefighters of course. EV's are much safer against the risk of fire both because it can't really happen often, and also because whenever it happens, the fire develops "slowly", within minutes (instead of seconds with gasoline), leaving a lot of time to people for leaving the car and getting in safety.

[BertTrack]

Hybrids and EV's have high amp fuses to shorten the time that it can be cause trouble.

[MrDude_1]

In electric motorcycles and cars, what safety equipment is in place (if any) to prevent arcing, short-circuiting or electrocution in the event of a crash that destroys the batteries? Obviously nothing will prevent this if the batteries are thrown from the vehicle, but in a conventional accident what keeps the vehicle safe to handle?

The first line is the build. You will notice that the actual cells in almost all EVs are all in a very solid well protected metal can of some kind. Inside that unit there is a contactor that disconnects both battery terminals. Production EV cars also have one or more loops that will disconnect the battery if cut.
After that there are fuses. If the battery is shorted, they should blow, also breaking the circuit. Finally there is a safety plug that disconnects the battery to make the car safe to work on.

So to answer your second question, if its a accident where the rescue needs to work on the car, they first disconnect the 12v car battery like any other car. This keeps the contactors from being enabled... but just incase as a backup, they can cut the battery loop. Some cars have them at both the front and the back, so that one is always accessible.

Since there are no hot parts on the car, theres less chance of fire as long as the battery pack is disconnected.