Quote:
Originally Posted by Skybird
But could you get electrocuted if you stand in the water near to the car?
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Very unlikely.
It requires a closed circuit, which also has to offer the lowest electric resistance. You'd still have to get very close to one of the poles of the accumulator before you'd receive a shock strong enough to cause you harm. Also accumulator cells (especially those in cars) usually have automatic safeties that shut the entire cell down in case of a short circuit. This usually ruins the cell, but should trigger if water comes into contact with the cell itself.
As you mentioned the electric eel: as long as it doesn't touch you the shock can't harm you.
EV accumulators usually are pretty well protected from water, and unless the protection has been damaged it takes considerable time before dangerous amounts of water can come in. The core cells of lithium based accumulators have to be built air tight anyway (like almost every battery). An explosion could happen in theory, but this qould require the cell to be damaged and the amount of water to be exactly right, neither too little (reaction takes too long) nor too much (cooling effect of water becomes too strong).
Currents on the chassis: a car's chassis always carries a current. The 12V-accumulator in any car uses the chassis as ground. The same as above applies: unless you create a closed circuit with your body offering the least electric resistance you are safe. A driver in a racing car after a bad accident is a slightly different matter, the chassis is checked to make sure that even if the driver is somehow electrically connected (i.e. touching conducting material at any point) to the high power system he doesn't close the circuit.
Fires: a car fire almost always leads to a total (constructive) loss of the car unless it's extinguished quickly. Again the shell protecting an EV's accumulator should hold long enough if it's undamaged. Once it's damaged it's another matter entirely, though.
Salt in winter: to keep this out an EV accumulator just needs to be splash resistant, which it always is. No trouble here.
Metal fires: the problem usually is aluminum, of which we use a lot (because it's so common), and it's actually not a problem of burning. Aluminum is quite reactive and readily reacts with oxygen, but the resulting aluminum oxide forms a layer that protects any underlying aluminum. This occurs naturally, but the oxide layer can be strengthened by anodizing (common procedure). The oxide layer is so strong that aluminum can melt inside it's own oxide layer without the liquid metal dropping out. It deforms, though, and that's what happens in a fire (like in the USS Belknap fire, for example): the heat from the fire melts the aluminum inside it's oxide layer.
Igniting everyday metals (so that they truly burn) requires insane amounts of energy. Of those metals magnesium is the easiest to ignite, but it requires in excess of 1000°C, way beyond your ordinary fire. Aluminum could be another candidate, but this requires even higher temperatures AND the rupturing of the oxide layer in the right moment. Igniting iron is simply not possible, it's very hard to do even in an atmosphere of pure oxygen.