Tesla: ‘There’s almost no reason to have a gas car’

[Ostfriese]

Originally Posted by Skybird

But could you get electrocuted if you stand in the water near to the car?

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.

[Skybird]

Thats an extensive answer!

[Ostfriese]

Originally Posted by Skybird

Thats an extensive answer!

Sorry for the length, but after 20 years in accumulator technology research I simply can't help it.

[Eichhörnchen]

Don't worry: he likes extensive answers

[Skybird]

Yeah, no worries at all! I already suspected after Ostfriese's reply that he knows that stuff a bit better himself. Gude Antwort, alter Friese!

[August]

I saw a video the other day about someone recovering a speedboat that had sat at the bottom of a lake for over three decades. They were able to get the engine running with not a lot of work. Think an EV would fare so well in a similar situation?

[Ostfriese]

Originally Posted by August

I saw a video the other day about someone recovering a speedboat that had sat at the bottom of a lake for over three decades. They were able to get the engine running with not a lot of work. Think an EV would fare so well in a similar situation?

Why shouldn't it? Compared to a combustion engine/drive train an electric motor/drive train has fewer mobile parts, and even if water enters the core of the motor the corrosion damage should be manageable.
In general this is more a question of corrosion rather than the type of engine used.

[August]

Originally Posted by Ostfriese

Why shouldn't it? Compared to a combustion engine/drive train an electric motor/drive train has fewer mobile parts, and even if water enters the core of the motor the corrosion damage should be manageable.
In general this is more a question of corrosion rather than the type of engine used.

With all the stories about EVs being useless after being submerged I was just wondering.

[Ostfriese]

Originally Posted by August

With all the stories about EVs being useless after being submerged I was just wondering.

You have to differentiate between the motor/drive train and the power source.

1) Both a combustion engine and an electric engine can survive prolonged periods submerged (and have done so in many cases), and as I said it's much more a question of the level of corrosion rather than the type of engine whether it can be used again with little effort.

2) For the power source it depends on the damage received, but in general electric power sources are more at riks in water compared to combustion engine fuel. The reason for that is rather simple: fuels (diesel, gasoline/petrol, kerosene or whatever you choose) are organic and usually hydrophobic and don't mix well with water (they are nonpolar substances), while the materials used to produce electric energy in batteries are hydrophilic (components need to be polar/ionic) and are more likely to be soluble in water. Any polar fuel (like ethanol/alcohol, for example) suffers from the same problem.

However, I doubt that any non-polar fuel that has been in direct contact with water for a prolonged time can directly be used to power an engine.

[August]

Originally Posted by Ostfriese

You have to differentiate between the motor/drive train and the power source.

1) Both a combustion engine and an electric engine can survive prolonged periods submerged (and have done so in many cases), and as I said it's much more a question of the level of corrosion rather than the type of engine whether it can be used again with little effort.

2) For the power source it depends on the damage received, but in general electric power sources are more at riks in water compared to combustion engine fuel. The reason for that is rather simple: fuels (diesel, gasoline/petrol, kerosene or whatever you choose) are organic and usually hydrophobic and don't mix well with water (they are nonpolar substances), while the materials used to produce electric energy in batteries are hydrophilic (components need to be polar/ionic) and are more likely to be soluble in water. Any polar fuel (like ethanol/alcohol, for example) suffers from the same problem.

However, I doubt that any non-polar fuel that has been in direct contact with water for a prolonged time can directly be used to power an engine.

But gas or diesel fuel in a gas powered engine is just a consumable whereas batteries in an EV must be replaced, correct?

[Ostfriese]

Originally Posted by August

But gas or diesel fuel in a gas powered engine is just a consumable whereas batteries in an EV must be replaced, correct?

Yes. Even if the cells aren't damaged and remain watertight you'd have to exchange the important substances, and while you could call them "consumables" the entire process is far more difficult.

[mapuc]

I got this idea of a company

What I need is a reinvention of the battery
an expert or three with knowledge in batteries.

And of course experts in developing and making cars.


I have this huge dream about building cars with removable batteries. Where the batteries has the size of an iPad and with a capacity 40-50.000 times higher than todays car batteries used in E-cars and weight 1/20 of a car battery.

I see how people remove the batteries, install them in a charging stations and next day they are fully loaded.

Markus

[August]

Originally Posted by mapuc

I got this idea of a company

What I need is a reinvention of the battery
an expert or three with knowledge in batteries.

And of course experts in developing and making cars.


I have this huge dream about building cars with removable batteries. Where the batteries has the size of an iPad and with a capacity 40-50.000 times higher than todays car batteries used in E-cars and weight 1/20 of a car battery.

I see how people remove the batteries, install them in a charging stations and next day they are fully loaded.

Markus

I can refuel my old gas powered vehicle in two minutes. Overnight charging does not cut the mustard. There have been instances where i've driven 800 miles in one single day. That's not happening with an EV.

[mapuc]

Originally Posted by August

I can refuel my old gas powered vehicle in two minutes. Overnight charging does not cut the mustard. There have been instances where i've driven 800 miles in one single day. That's not happening with an EV.

Thank you so much Dave for helping me remember.

My idea is that these batteries can be recharged within 30 min or less
and the battery will be neutral to temp. Same outcome whether it's minus 20 degrees C or + 25 Degrees C.

I imagine the car having 4 batteries.
1+2 batteries Engine
1 battery for the aircondition
1. battery for the electricity.

Markus

[Ostfriese]

Sorry, Markus, that's not going to happen. Downsizing batteries/accumulators without downsizing the capacity has it's limits, and we already are quite close to these limits, as long as we stick to electrochemical reactions, and for those there are no alternatives in sight. There are a few theories about using crystals as energy storages, but that's barely more than science fiction.