high voltage battery

[firemandave]

What if a 300 Volt Lithium-ion dry cell battery was submerged in water. Would the battery discharge? Would it make a difference if it was in salt or fresh water? Would a voltage gradient be formed around the battery or would the electrons flow in a direct line between the battery terminals? How large would the area with the voltage gradient be?

Thanks for your answers.

 

[dbuckley]

Pure water doesn't conduct at all well so if you chuck it into pure water then not much will happen.

Chuck it into the briny, and there will be conduction between every point of differential potential; electricity takes all possible paths. The battery will discharge.

 

[Volta]

What if a 300 Volt Lithium-ion dry cell battery was submerged in water. Would the battery discharge?

Yes.

Would it make a difference if it was in salt or fresh water?

Yes, but the 'fresh' water will still be quite conductive enough, IMO.

Would a voltage gradient be formed around the battery

Yes.

. . . How large would the area with the voltage gradient be? . . .

Depends on the quality of the water, but I don't think it would be very large.

 

[LarryFine]

Would a voltage gradient be formed around the battery or would the electrons flow in a direct line between the battery terminals?

Most likely, the gradients would flow between the posts similarly to the lines you've seen in pictures of magnets with iron filings, or in drawings.

 

[Volta]

Most likely, the gradients would flow between the posts similarly to the lines you've seen in pictures of magnets with iron filings, or in drawings.

Great visual!

 

[zog]

What if a 300 Volt Lithium-ion dry cell battery was submerged in water. Would the battery discharge? Would it make a difference if it was in salt or fresh water? Would a voltage gradient be formed around the battery or would the electrons flow in a direct line between the battery terminals? How large would the area with the voltage gradient be?

Thanks for your answers.

Salt water in the battery will cause major gassing to occur and a large hydrogen explosion.

 

[LarryFine]

Salt water in the battery will cause major gassing to occur and a large hydrogen explosion.

Way cool!

 

[benaround]

Way cool!

Unless you are a 'fireman' and this is an electric car in the pond !

 

[broadgage]

Fresh water conducts electricity, though not very well.
I would expect that a 300 volt battery immeresed in fresh water would discharge relatively slowly.
The voltage gradient around the battery would probably be dangerous to anyone in the water if they were very close to the batttery. The human body is a better conductor than fresh water, therefore a fair bit of current could flow the body, perhaps with fatal results.
A lot would depend on the terminal layout and spacing.

Sea water is a much better conductor than fresh, and perhaps suprisingly this should reduce the risks to anyone in the water.
A much greater current would flow through the salt water, thereby discharging the battery very rapidly, perhaps before anyone got dangerously close.
Such a rapid discharge might tend to overheat the battery, but the water would probably keep it cool.
Also the sea water is a better conductor than the human body, and therefore might shunt or bypass most of the current around, rather than through the person.

If fresh or salt water entered the sealed battery cells than an explosion is likely since lithium reacts vigouresly with water to produce hydrogen, which is flammable. The cells are however well sealed and are designed to withstand impact and water immersion.

 

[ggunn]

Fresh water conducts electricity, though not very well.
I would expect that a 300 volt battery immeresed in fresh water would discharge relatively slowly.
The voltage gradient around the battery would probably be dangerous to anyone in the water if they were very close to the batttery. The human body is a better conductor than fresh water, therefore a fair bit of current could flow the body, perhaps with fatal results.
A lot would depend on the terminal layout and spacing.

Sea water is a much better conductor than fresh, and perhaps suprisingly this should reduce the risks to anyone in the water.
A much greater current would flow through the salt water, thereby discharging the battery very rapidly, perhaps before anyone got dangerously close.
Such a rapid discharge might tend to overheat the battery, but the water would probably keep it cool.
Also the sea water is a better conductor than the human body, and therefore might shunt or bypass most of the current around, rather than through the person.

If fresh or salt water entered the sealed battery cells than an explosion is likely since lithium reacts vigouresly with water to produce hydrogen, which is flammable. The cells are however well sealed and are designed to withstand impact and water immersion.

While distilled water is a very bad (theoretically zero) conductor of electricity, it doesn't take much ionic content to turn it into a pretty good conductor. Even water out of the tap is plenty conductive enough to be very dangerous when electricity is around. A kid I knew in college was standing knee deep in a temporary wading pool made from 2X4's and plastic sheeting that was filled with tap water. He reached out and picked up a plugged in circular saw that was lying on the ground next to the pool and it killed him.

As to the Lithium in Li-ion batteries; I don't know that much about the technology, but although it is true that metallic Lithium interacts violently with water, I don't believe that there is metallic Lithium in a Li-ion battery. I'm pretty sure that what's in them is a Lithium salt. I don't think there is an explosion danger from Lithium batteries in water; people take Li-ion batteries diving in cameras and such all the time.

Salt water does a number on batteries very quickly. Once, I was diving in salt water when my dive light flooded. It quit working immediately and by the time the dive was over (about 30 minutes later) the D sized alkaline battery casings had corroded through and the water trapped in the light housing was black sludge.