this post was submitted on 04 May 2024
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[–] dual_sport_dork@lemmy.world 64 points 4 months ago (33 children)

Well, only relatively.

In order to work batteries need to have a certain amount of instability built in, on a chemical level. Them electrons have to want to jump from one material to a more reactive one; there is literally no other way. There is no such thing as a truly "safe and stable" battery chemistry. Such a battery would be inert, and not able to hold a charge. Even carbon-zinc batteries are technically flammable. I think these guys are stretching the truth a little for the layman, or possibly for the investor.

Lithium in current lithium-whatever cells is very reactive. Sodium on its own is extremely reactive, even moreso than lithium. Based on the minimal lookup I just did, this company appears to be using an aqueous electrolyte which makes sodium-ion cells a little safer (albeit at the cost of lower energy density, actually) but the notion that a lithium chemistry battery will burn but a sodium chemistry one "won't" is flat out wrong. Further, shorting a battery pack of either chemistry is not likely to result in a good day.

[–] catloaf@lemm.ee 7 points 4 months ago (11 children)

If you poke a hole in it, is it just as exciting as lithium?

[–] Gormadt@lemmy.blahaj.zone 19 points 4 months ago (9 children)

A different kind of excitement without flames.

Sodium cells have been out of the lab for at least 8 months now.

They're still a bit pricey but the price is quickly falling

[–] soEZ@lemmy.world 2 points 4 months ago* (last edited 4 months ago) (2 children)

These are more fun then lipos... I wounder if u pack a tesla full of these..will it manage to achive escape velocity after a crash? I mean gas cars and lithium batteries right now just turn car into lots fo smoke and flames..but these might really change how we see crashes...

Edit: I feel like I need to add an /s somewhere...the amout of serious replies to this comment are concerning 🤦

[–] Nindelofocho@lemmy.world 7 points 4 months ago (2 children)

That explosion doesent seem much bigger than a firework thats smaller than the battery’s size. With as much as a car weighs and the amount we already do to protect batteries in electric cars i imagine the explosion from these could be easier to manage safely than a lithium fire. I also wonder how harmful the fumes are compared to lithium

[–] Gormadt@lemmy.blahaj.zone 7 points 4 months ago (2 children)

Especially considering there's no fire from a sodium cell, just a quick bang. They definitely seem a lot safer.

[–] TimeSquirrel@kbin.social 3 points 4 months ago (1 children)

We already know how to take care of this in big capacitors. You put a breakaway vent in.

[–] cybersin@lemm.ee 1 points 4 months ago

Yep, cylindrical Li-ion cells like the 18650 already do this.

[–] cybersin@lemm.ee 3 points 4 months ago

Yep, less/no fire is very important when creating battery banks with many cells. The probability of single cell failure spreading to adjacent cells is reduced, making a catastrophic failure of the entire bank less likely.

[–] soEZ@lemmy.world 1 points 4 months ago

My hopes of flying cars has been dashed 😐

[–] cybersin@lemm.ee 2 points 4 months ago

LiPo batteries of the same capacity actually have the potential to be much more dangerous than the sodium cell shown here.

LiPo packs typically use flat, soft walled cells which are far more susceptible to being punctured. In the event of a puncture or overcharge event, high temperature enduring flames are produced, with the severity and duration largely depending on the amount of energy within the cell. LiPo batteries also degrade at a much faster rate (both over time and with charge cycles) and have been known to spontaneously combust in storage while at rest.

With the sodium battery, the thrust produced by the puncture could have been easily been overcome by properly securing the cell.

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