Explosion-Proof Lithium-Ion Battery Shuts Down At High Temperatures (thestack.com)

An anonymous reader writes: Scientists have designed a lithium-ion battery that self-regulates according to temperature, to prevent itself from overheating. Reaching extreme temperatures, the battery is able to shut itself down, only restarting once it has cooled. The researchers designed the battery to shut down and restart itself over a repeated heating and cooling cycle, without compromising performance. A polyethylene film is applied to one of the electrodes, which expands and shrinks depending on temperature, to create a conductive/non-conductive material.

Comments

Re:What about

[Racemaniac]

If you had read to the end of the summary, you would have noticed that it's a passive film that stops conducting if it gets too hot.

Been done

[pcjunky]

If you take apart most Li-Ion battery packs from laptops you will find a thermistor. This is to help prevent the battery from overheating while charging/discharging. Nothing new here except perhaps they are putting them in smaller single cell Li-Ion batteries like cell phone batteries.

Re:Been done

[drinkypoo]

If you take apart most Li-Ion battery packs from laptops you will find a thermistor. This is to help prevent the battery from overheating while charging/discharging.

More accurately, it is to help the charger not explode the batteries by charging them too quickly. It's usually used for no other purpose although it's not that unusual for a laptop to tap into it to also report the battery temperature. This is also typically done in power packs for cordless tools. Most of them don't have any kind of over-current protection, though. You can overheat them by misusing the tool, and for the same reason, laptop batteries can combust when one cell goes bad. The idea here is to prevent that by simply shutting off the battery when one cell goes tits up. There's a charge controller in the pack, but there's not a discharge controller.

Re:Been done

[tlhIngan]

If you take apart most Li-Ion battery packs from laptops you will find a thermistor. This is to help prevent the battery from overheating while charging/discharging. Nothing new here except perhaps they are putting them in smaller single cell Li-Ion batteries like cell phone batteries.

LiPos have them as well for the same reason.

But this isn't a thermistor that controls a circuit - it's a new cell construction technique that basically has the cell turn itself off when it gets too hot, not externally via a circuit (that may or may not exist, or may be defeated because the Chinese maker of the pack wanted to save a buck).

Yes, counterfeit battery packs exist, and they often are missing the safety circuits as well as using dodgy cells. While there are often very good 3rd party suppliers of battery packs, there are dozens more dodgy sellers of questionable quality 3rd party packs ready and willing to sell you incendiary devices. Probably the reason why those "hoverboards" we see keep catching on fire.

So having the cell be able to protect itself would provide a big increase in safety if you ever find yourself stuck using some crappy quality 3rd party battery packl

Re:What about

[RghtHndSd]

There needs to be a mod option "Wrong".

Re:Can it be done effectively on a per-cell basis?

[damn_registrars]

i would hope that your device has some sort of temp monitor to give you some warning

That is a really good point. I can't say I routinely check to see what my battery temperature is at:

>acpi -t

Thermal 0: ok, 58.0 degrees C

I wonder about dog's teeth.

[SharpFang]

Recently mother, extremely unnerved, called me - claiming her dog brought a dud firework home and it exploded, nearly causing a fire.

Later it was revealed it was not a firework. The dog stole a Li-Ion battery for my phone from my room. Biting into it shorted it, and the battery exploded hard, shooting ribbons of burning lithium all around like a true firework.

So... would this new invention prevent it?

Re:Explosion resistant?

[sjames]

Explosion resistant is a much better term for this. It addresses some but not all reasons a LiIon battery might "vent with flame".

Re:Recharging or on load?

[fnj]

A runaway LiIon is not just a "fire". There can be violent outgassing and blowtorching. If you try to hermetically close the ammo box while charging, it could easily be blown apart and imitate a grenade. If you DON'T seal it, the gas and flames could be voluminously emitted from the container.

I would think a fireplace would be far safer. If you don't have one, mabe you could stack a labyrinth of firebricks on a big metal base. If the weather is nice and you have a sandy or gravelly or paved driveway with plenty of room, the center of that should be pretty safe. I use the inside of an oven which is otherwise unused, but most will not have the luxury of such a resource.

Re:Can it be done effectively on a per-cell basis?

[PPH]

shut down quickly in response to heat could be a bad thing

Right in the middle of a Call of Duty session and the laptop shuts down. You'd have to abort the mission and lose who knows how many points. Complete disaster.

Re:What about

[Zaowulf]

Dammit Jim I'm a stage designer not an engineer!