The Dangers of Lipo Batteries

[Jdege]

Originally Posted by newhaul

Lifepo4 will not have a thermal runaway by tag standard definition . ie it will heat up to the point that the thermal reaction becomes self sustaining resulting in the internal components of the cell catching fire.
One Chinese government sponsored study not withstanding . there are many videos on youtube of official agencies testing with no fire from the cell

My understanding was that while it would burn, if ignited, it would not spontaneously ignite.

[Simi 60]

Originally Posted by Melbourne Park

“We can’t bust heads like we used to—but we have our ways. One trick is to tell them stories that don’t go anywhere like the time I caught the ferry over to Shelbyville. I needed a new heel for my shoe, so I decided to go to Morganville which is what they called Shelbyville in those days. So, I tied an onion to my belt which was the style at the time. Now, to take the ferry cost a nickel. And in those days, nickels had pictures of bumblebees on ‘em. ‘Give me five bees for a quarter,’ you’d say. Now, where were we? Oh, yeah! The important thing was that I had an onion on my belt which was the style at the time. They didn’t have white onions because of the war. The only thing you could get was those big yellow ones.”

It's the gift that keeps on giving

[newhaul]

Originally Posted by Jdege

My understanding was that while it would burn, if ignited, it would not spontaneously ignite.

Actually one study video I posted shows that the plastic cased ones will burn if you light the plastic on fire but even the application of an open flame on the metal cased ones like my bank is made with there is no chance of actual fire from the batteries . now the rest of the electrical system yes but cells alone nope

[s/v Jedi]

No, overcharging a LFP house battery can not result in a thermal runaway regardless of the definition used.

The laboratory experiment that achieved this used a 35V per cell charge voltage to achieve the thermal runaway. The smallest batteries used on boats are 12V with four LFP cells in series so to replicate this experiment doesn’t just require one to remove the BMS but also have a charger that outputs 140V charge voltage at an enormous current.

This is impossible. Only in laboratory conditions can this be achieved.

[sailorboy1]

Why is this thread still in basic argument stage?????

Last I knew ABYC tried to cause a problem with LFP and for all that matters couldn't.

If someone has an actural case of a proven LFP thermal runaway on a boat please PM me the link.

[BlueH2Obound]

Originally Posted by sailorboy1

Why is this thread still in basic argument stage?????
Last I knew ABYC tried to cause a problem with LFP and for all that matters couldn't.
If someone has an actural case of a proven LFP thermal runaway on a boat please PM me the link.

Oh come on, sailorboy, don't let facts get in the way of a good off the wall discussion!

I too was pretty surprised that ABYC couldn't figure out how to get a LiFePO4 battery to catastrophically fail. The next item on their agenda, according to the ABYC president is to do more testing while submerging the LiFePO4 battery in salt water . . .

hmmmm, if my LiFePO4 batteries are underwater, it would mean that my "draft" has increased by about 5 feet . . . . which is pretty much the description of a boat that has sunk, at least partway. As I paddle away in my raft, or in my dinghy, what happens to those LiFePO4 cells is probably going to be the least of my worries . . .

[Melbourne Park]

Originally Posted by Simi 60

It's the gift that keeps on giving

Please delete the text which you said I posted. I never have said any of that .

[Melbourne Park]

Originally Posted by s/v Jedi

No, overcharging a LFP house battery can not result in a thermal runaway regardless of the definition used.

The laboratory experiment that achieved this used a 35V per cell charge voltage to achieve the thermal runaway. The smallest batteries used on boats are 12V with four LFP cells in series so to replicate this experiment doesn’t just require one to remove the BMS but also have a charger that outputs 140V charge voltage at an enormous current.

This is impossible. Only in laboratory conditions can this be achieved.

There are several ways that studies discuss potential for thermal runaways of LFP batteries. Just because a lab uses one type of method to ignite LFP batteries, does not mean their results have no meaning. They could use dozens of ways to get LFP cells to a critical temperature.

Obviously consideration of placement of LFP and the potential for things going wrong is worthwhile. Counter to that view is - "LFP cannot burn, its perfectly safe, I can put it anywhere I like."

It seems to me that the critical temperature is from 124 C to 128 C (degrees).

It seems too, that the higher the state of charge, the higher the temperature of the thermal runaway.

Now, many advertisements I have read, say that the LFP cannot burn, and that for instance, they require 500 C to burn, so they are completely safe. My view is those advertisements are false.

Mistreat electronics and one may pay a price.

And stupid behaviour with LFP might cause issues.

https://www.youtube.com/watch?v=07BS6QY3wI8

Abstract
The combustion behavior of 50 Ah LiFePO4/graphite battery used for electric vehicle is investigated in the ISO 9705 combustion room. The combustion is trigged by a 3 kW electric heater as an external thermal radiative source, and then the surface temperature, combustion behavior, heat release rate, flame temperature and mass loss rate are obtained. The thermal runaway occurs when the battery surface temperature reaches 126.7 ± 2.2 °C and releases the combustible gases. After its ignition, the combustion generally undergoes first jet fire stage, stable combustion stage, second even third jet fire stage, final stable combustion stage and extinguishes stage. The maximum heat release rate reaches 64.32 kW and the maximum heat release is 13.74 MJ. The heat release rate is closely synchronous with the mass loss rate, and the mass loss ratio reaches to 26.9%. These fundamental data can provide basic knowledge for the battery performance based fire safety design.

[newhaul]

Originally Posted by Melbourne Park

There are several ways that studies discuss potential for thermal runaways of LFP batteries. Just because a lab uses one type of method to ignite LFP batteries, does not mean their results have no meaning. They could use dozens of ways to get LFP cells to a critical temperature.

Obviously consideration of placement of LFP and the potential for things going wrong is worthwhile. Counter to that view is - "LFP cannot burn, its perfectly safe, I can put it anywhere I like."

It seems to me that the critical temperature is from 124 C to 128 C (degrees).

It seems too, that the higher the state of charge, the higher the temperature of the thermal runaway.

Now, many advertisements I have read, say that the LFP cannot burn, and that for instance, they require 500 C to burn, so they are completely safe. My view is those advertisements are false.

Mistreat electronics and one may pay a price.

And stupid behaviour with LFP might cause issues.

Interesting all of the other video tests with verified lifepo4 cells there was absolutely no self ignition. How do we know these are infact lifepo4 cells .

[newhaul]

Originally Posted by Melbourne Park

There are several ways that studies discuss potential for thermal runaways of LFP batteries. Just because a lab uses one type of method to ignite LFP batteries, does not mean their results have no meaning. They could use dozens of ways to get LFP cells to a critical temperature.

Obviously consideration of placement of LFP and the potential for things going wrong is worthwhile. Counter to that view is - "LFP cannot burn, its perfectly safe, I can put it anywhere I like."

It seems to me that the critical temperature is from 124 C to 128 C (degrees).

It seems too, that the higher the state of charge, the higher the temperature of the thermal runaway.

Now, many advertisements I have read, say that the LFP cannot burn, and that for instance, they require 500 C to burn, so they are completely safe. My view is those advertisements are false.

Mistreat electronics and one may pay a price.

And stupid behaviour with LFP might cause issues.

If your afraid of them don't use them but don't look into what all can go wrong with a flooded lead acid battery when just charging normally. Hydrogen reacts rather violently

[Simi 60]

Originally Posted by Melbourne Park

.

Mistreat electronics and one may pay a price.

And stupid behaviour with LFP might cause issues.

]

Makes mental note to not stab batteries with giant metal bar.

Filed away with don't stick knives in PowerPoints and don't jump out of windows thinking I can fly.

[s/v Jedi]

At least the scientific research showed a thermal runaway induced by wild 10-fold overcharging. This video, if genuine, shows an internal short caused by piercing it with a conductive metal spear, leaving internal damage that also shorts the cell. Yes, that gets hot. They tried it using the terminals before but those melted away too.

The short will get very hot and the rise in temperature will open the over pressure valve, with electrolyte gas escaping. This gas did not ignite until a big spark was introduced from another piercing with the spear.

My question is if this escaping plume of gas and maybe electrolyte particles is indeed flammable. If it is, then you should only use ignition protected gear in the battery compartment. Note that class-T fuses require a special fuse block for ignition protection.

BTW, that (presumably) LFP cell was not on fire. The escaping vapor was.

Again we see claims that have nothing to do with actual use of LFP based batteries as house batteries in boats. The dangers of cobalt based lithium chemistries are not comparable in any way. I see two possible reasons for these attempts to “cancel” LFP: those who do this have either cobalt based chemistries or they have no lithium at all and need a reason for explaining why they are staying behind.

[rslifkin]

Originally Posted by s/v Jedi

My question is if this escaping plume of gas and maybe electrolyte particles is indeed flammable. If it is, then you should only use ignition protected gear in the battery compartment. Note that class-T fuses require a special fuse block for ignition protection.

Even if the gas is flammable, we're already used to the concern of hydrogen from lead acid batteries. So battery compartments should still be ventilated with LFP. And ideally, no other electrical equipment should be right next to the batteries (where it could be exposed to a concentrated gas plume). Making sure that the battery installation is protected from being punctured by anything that gets loose in a knockdown, etc. will also go a long way toward avoiding this scenario.

[Jdege]

Seems to me that dangers are situational - the question isn't whether there are risks, but what choices we need to make in installation and operation to mitigate those risks.

[newhaul]

Originally Posted by Jdege

Seems to me that dangers are situational - the question isn't whether there are risks, but what choices we need to make in installation and operation to mitigate those risks.

Yep a properly constructed and secured battery box covers it all .
Just like what the ABYC recommends for lifepo4 installation.