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Comment by lnsru | Hacker News Reader

There was a story about ship full of shiny new Volkswagens sinking to the bottom of the ocean: https://m.slashdot.org/story/396813 Bad source, German newspapers had more detailed reports in German. Basically burning ship with electric cars can’t be saved. That’s probably also valid for discarded batteries.

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Maybe a stupid question, but does a Li-ion battery need to be charged in order to burn like this?

I'm not talking about the batteries that start the fire. Obviously they won't cause an electrical fire if they're not charged. I'm talking about the other batteries nearby that get heated up by the initial fire.

Most lithium ion batteries contain mixtures of liquid organic carbonates as electrolytes. They range from moderately to very flammable. Here's some vendor information on dimethyl carbonate, one of the more flammable electrolyte components:

https://smc-global.com/dimethyl-carbonate/

https://smc-global.com/wp-content/uploads/2021/04/M3574_DIME...

These liquids can burn regardless of the battery state of charge.

Incidentally, besides the flammability, the electrolyte is otherwise quite harmless. It's comparable to ether, alcohol, or acetone.

There are other components in the battery which are both toxic and corrosive to electronics. Please be careful of any broken batteries and if there is a fire don't breath the fumes!

This is true, but pretty badly misstating the risk analysis. Lithium electrolytes are, on the whole, "flammable" in exactly the same way that things like grain shipments are flammable. It's a real risk, and requires engineering to address. They aren't remotely "dangerous" materials.

Sort of like how a transformer explosion is typically a lot worse due to the oil used to cool larger transformers. The oil is great because it allows for heat transfer well, fits into all the nooks and crannies and isn't conductive to electricity. But, the oil is still flammable. And then, trying to put out the flames, the combination of electricity and oil makes using water a very bad idea.

Yes - even Lithium Ion batteries which are practically dead may combust if the pouch is pierced (in pouch based ones of course). I recall vaguely shipping standard operating procedure of around 10% charge for bulk batteries and 50% charge for electronics which contain them but don't quote me on those numbers. But either way more energy means bigger, more, and longer lasting flames.

They cannot be fully discharged without permanently damaging the cells, so Li-ion batteries are always shipped with some charge.

Actually most RoRo carriers, once they start to burn sink with the fire being unextinguishable.

Oil, Gas & Tires burn well enough. No batteries needed.

based on recent mishaps for "pure car carrier" RoRos they seem to have catastrophic failures based on being top-heavy or ballast problems, I can recall at least 3 within the past 20 years that have toppled over on their sides in catastrophic events that are non fire related.

Or leaving the doors open: https://www.bbc.co.uk/news/uk-england-suffolk-25446228 . I've deliberately linked a page to the memorial. Plenty of links to the cause.

If you're trying to be respectful by deliberately linking to a memorial, it's rather undermined by linking to one for a completely different disaster from what you're describing. The European Gateway collided with another ship. Doors being left open was the Herald of Free Enterprise.

while I wouldn't say that it's a totally "solved" problem, some of the terrible mishaps of bow doors on roro ships that occurred in the past 30-40 years seem to have led to much more stringent operational and engineering standards for door locking and latching systems.

Believe it's the battery short and discharge that starts the heat and fire. And to prevent damaging the batteries they ship them 50% charged

Newer electric cars are LiFePo and don't catch fire and are less dangerous

While LiFePO4 is a safer chemistry than batteries using NMC, they can absolutely still catch fire. The only Lithium based chemistry that I know off that you might be able to describe as "don't catch fire" is Lithium Titanate/Titanium Oxide (LTO), but even then, in a bad enough situation I believe it will still ignite though briefly but won't sustain. LiFePO4 will still ignite and sustain a fire from the demonstration videos I have seen.

I don't know enough about the "Blade" battery chemistry but early info I have seen seems to indicate a very high level of safety as well, more so than current LiFePO4 setups.

The blade battery is LoFePO4 and the video released show them only heating and smoking after being punched and short circuited

Well if you watch YouTube most nail puncher tests of LFP don't catch fire. There is one video were someone hammers two holes in the battery and it catches fire

>Basically burning ship with electric cars can’t be saved.

The fire was put out and it was being towed to port when it sank in heavy seas. The battery cars may or may not have caused the fire, we just don't know.

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