The Dangers of Lipo Batteries

[newhaul]

Originally Posted by CaptainRivet

you can brute force a LifePo4 into thermal runaway, you just need enough volts and amps over a long enough periode to create that...you need a lot and long but its possible and before a lot other stuff will end up in smoke before the Lifepo4 does. Every AGM would get a thermal runaway long long before that under this conditions or a lead would explode much much earlier.
And the BMS prevents a LifePo4 even from that highly unlikly scenario.

Actually the science and controlled experiments have proven that you can not cause a thermal e
Runaway in lifepo4 prismatic cells .

[oubeta]

I had 2 ONEAN batteries for a electric surfboard just sitting on my boat. I wasn't even charging them. One had a thermal runaway at 3am setting both of them on fire while we were asleep. We thought someone was on our flybridge shooting down through the boat. It shounded like an AK going off. It was impossible to put out. I hit it with 3 big fire extinguishers and it was like spitting on a bonfire.
I had my wife and 4 kids on the boat on a remote island with no fire fighting. We barely made it off. It burned for 45min and sank. Brand-new power cat.

From my research, that particular board has burned more than a few boats.

It was a year long fight with the insurance company.

[Nicholson58]

Originally Posted by Melbourne Park

In Australia, insurance companies make using Lithium very difficult. Their ploy is to insist on professional installation, so they can sue the installer. So the installers won't install lithium. So insurance is difficult to get for sail boats with Lithium Phosphate Iron.

My boat is light, I wanted to keep it that way, but I've had to put in lead acid. I would have much preferred the lighter alternative.

There are issues with Lithium Phosphate Iron though ... they are not "drop in" for boats. There are lots of stories about what might happen being inverted in Salt water ... I rang support at Lifeline / Concord batteries, and asked them ... the chap laughed and said "any battery in salt water is bad news". Now - that was my recollection of what he said ... so I may have misquoted him.

An acquaintance of mine has lithium in her solo race boat. She said that many people were concerned about the America's cup boat (an English boat) that tipped over and then inverted, and had a lithium fire ... now why would an AC boat not have Lithium Phosphate Iron batteries? But perhaps they did not ... but the lady I know is English, and was concerned, because solo or short hand sailors can invert their boats.


Here is what one report said, it happened a few weeks ago:
https://www.sail-world.com/news/2584...t-catches-fire

"After initially lying on its side, T6 rolled over to fully invert in the water with mast and double skinned main sail submerged, work quickly began to get her back upright.

The shore crew and sailors worked together for over two hours and after initially righting T6 back on its side they were able to fully right the yacht. T6 was then side towed by support boat back to the team base, where a full assessment of damage is under way.

The team also faced further challenges when the lithium batteries, that powers the yachts systems, reacted to seawater ingress causing a fire on board. The response was well managed with specialist training coming to the fore to mitigate the damage."

I think the batteries were NMCs though. They are used for electrical outboard motors I think. Any incident is bad for the reputation of Lithium phophate iron batteries.

Annoyingly too, there can be a significant quality difference in all batteries, which is complicated by the complexity of the various components that make up these batteries, compared to the non digital "mechanical" nature of lead acid.

By the time your boat is inverted, you have more to worry about than batteries of any kind. 🙄

[wholybee]

Originally Posted by newhaul

Actually the science and controlled experiments have proven that you can not cause a thermal e
Runaway in lifepo4 prismatic cells .

I have read several scientifically controlled experiments that did get LFP cells into thermal runaway.

However it seems that thermal runaway in a scientific sense doesn't necessarily equate to a _complete_ runaway. To get the cells into runaway, they had to be overcharged, with a high current sustained to them, and at the same time have an external heat applied to them. Which was done in a controlled way with an electric coil. They "ran-away" in the sense that a chemical reaction took place that then raised the temperature further, and after removing the charger and the external heat source the reaction continued and the cells did not cool down, but continued to melt.

Those conducting the experiments (Chemists or Physicists, I believe) deemed that to be thermal runaway, that the cells ran up to a higher temperature, and could not be "put-out" with normal measures, fire extinguisher, water, etc. Who am I to argue with scientists on the matter, but the temperature ultimately stabilized at a temperature just below that of what is required to ignite wood, but high enough to make it smolder. To a non-scientific person, that is not thermal runaway. There was no fire, just a very hot melted battery.

Anyway, I only bring this up because it is possible to find work that proves LFP can go into thermal runaway, and so there will always be that argument that it _can_ happen even if it is unlikely. I think it is important to understand what actually happens during that event and that thermal runaway with LFP doesn't equate to an uncontrollable fire. It is just a hot melted battery.

For sure, the safety of LFP is very well tested, lets not forget LFP are not new, but several decades old. A whole lot of science knowledge has been gained in that time. The only "issue" is that the media, and hence forth the public, can't differentiate between various lithium battery types.

[wholybee]

Originally Posted by oubeta

I had 2 ONEAN batteries for a electric surfboard just sitting on my boat. I wasn't even charging them. One had a thermal runaway at 3am setting both of them on fire while we were asleep. We thought someone was on our flybridge shooting down through the boat. It shounded like an AK going off. It was impossible to put out. I hit it with 3 big fire extinguishers and it was like spitting on a bonfire.
I had my wife and 4 kids on the boat on a remote island with no fire fighting. We barely made it off. It burned for 45min and sank. Brand-new power cat.

From my research, that particular board has burned more than a few boats.

It was a year long fight with the insurance company.

Those batteries were NOT Lithium Iron Phosphate. Which is the whole conversation, that LFP batteries don't do that, ever. LFP batteries safety should not be thrown into the same category as other Lithium types.

I hope at least, that you were eventually successful with your insurance claim, and I hope the battery/board manufacture had to pay for part of it as well.

[wholybee]

Originally Posted by CaptainRivet

agree with all you stated except this. Thats only correct for LTO, thats why I always state you don't need any BMS for a 1 or 2P6S LTO as its not economical for it, from 12S=24V you should due to ecomonic reasons.
But you always need a BMS for LifePo4.
The BMS protects Lifepo4 from damage to make it safer. Eg with how much amps and voltage did they overcharge the Lifepo4?

you can brute force a LifePo4 into thermal runaway, you just need enough volts and amps over a long enough periode to create that...you need a lot and long but its possible and before a lot other stuff will end up in smoke before the Lifepo4 does. Every AGM would get a thermal runaway long long before that under this conditions or a lead would explode much much earlier.
And the BMS prevents a LifePo4 even from that highly unlikly scenario.

Read my other reply. Current alone won't create thermal runaway, and if it thermal runaway does happen, it isn't a fire, just a ruined battery.

[s/v Jedi]

Originally Posted by wholybee

I have read several scientifically controlled experiments that did get LFP cells into thermal runaway.

However it seems that thermal runaway in a scientific sense doesn't necessarily equate to a _complete_ runaway. To get the cells into runaway, they had to be overcharged, with a high current sustained to them, and at the same time have an external heat applied to them. Which was done in a controlled way with an electric coil. They "ran-away" in the sense that a chemical reaction took place that then raised the temperature further, and after removing the charger and the external heat source the reaction continued and the cells did not cool down, but continued to melt.

Those conducting the experiments (Chemists or Physicists, I believe) deemed that to be thermal runaway, that the cells ran up to a higher temperature, and could not be "put-out" with normal measures, fire extinguisher, water, etc. Who am I to argue with scientists on the matter, but the temperature ultimately stabilized at a temperature just below that of what is required to ignite wood, but high enough to make it smolder. To a non-scientific person, that is not thermal runaway. There was no fire, just a very hot melted battery.

Anyway, I only bring this up because it is possible to find work that proves LFP can go into thermal runaway, and so there will always be that argument that it _can_ happen even if it is unlikely. I think it is important to understand what actually happens during that event and that thermal runaway with LFP doesn't equate to an uncontrollable fire. It is just a hot melted battery.

For sure, the safety of LFP is very well tested, lets not forget LFP are not new, but several decades old. A whole lot of science knowledge has been gained in that time. The only "issue" is that the media, and hence forth the public, can't differentiate between various lithium battery types.

Well, that is not a thermal runaway. It is incinerating.

A thermal runaway is a process where overcharging alone will trigger it and it will “run away”, i.e. get hotter and hotter by itself until it burst in flames.

[Chotu]

now that I have used these batteries for a while, I feel very confident in them. As far as safety goes.

The old FLAs were creating an acidic environment, offgassing, corroding the connections. That’s a hazard in itself. The quickly corroded connections of FLAs up the resistance, creating heat which could result in an electrical fire.

LiFePO4s don't have that hazard.

How about a knockdown? How about all the acid that spills out and no more battery after that?

and certainly there are plenty of examples of FLA batteries exploding in people's faces.

One other small detail is that if they are offgassing in an enclosed area, it will set off your carbon monoxide detector and confuse you.

but these LiFePO4 batteries seem pretty inert. The chemistry involved isn’t nearly as threatening. they can also take an incredible amount of power. I can put 70 A into my 400 AH bank when empty. And that’s just because that’s all I can put out. I don’t have a charging source higher than that. I have certainly felt the old lead acid batteries heat up when giving them a good push.

It’s really hard to see why you wouldn’t use these batteries. They are so superior.

[wholybee]

Originally Posted by s/v Jedi

Well, that is not a thermal runaway. It is incinerating.

A thermal runaway is a process where overcharging alone will trigger it and it will “run away”, i.e. get hotter and hotter by itself until it burst in flames.

I agree with you and that is certainly how I have always defined it. I am just pointing out that several studies I have read define it differently, and that difference should be pointed out if people are going to be afraid of LFP going into thermal runaway and bursting into flames, and/or argue if thermal runaway can happen on LFP. The flames part does not happen.

[newhaul]

Originally Posted by Chotu

now that I have used these batteries for a while, I feel very confident in them. As far as safety goes.

The old FLAs were creating an acidic environment, offgassing, corroding the connections. That’s a hazard in itself. The quickly corroded connections of FLAs up the resistance, creating heat which could result in an electrical fire.

LiFePO4s don't have that hazard.

How about a knockdown? How about all the acid that spills out and no more battery after that?

and certainly there are plenty of examples of FLA batteries exploding in people's faces.

One other small detail is that if they are offgassing in an enclosed area, it will set off your carbon monoxide detector and confuse you.

but these LiFePO4 batteries seem pretty inert. The chemistry involved isn’t nearly as threatening. they can also take an incredible amount of power. I can put 70 A into my 400 AH bank when empty. And that’s just because that’s all I can put out. I don’t have a charging source higher than that. I have certainly felt the old lead acid batteries heat up when giving them a good push.

It’s really hard to see why you wouldn’t use these batteries. They are so superior.

And if you had the capability the 400ah could easily handle just over 5 times that charging rate. But I would recomend not going above a .5C charge rate ( for your 400ah that would be 200mp charging. Yes most chargers are stackable .

[newhaul]

Originally Posted by wholybee

I have read several scientifically controlled experiments that did get LFP cells into thermal runaway.

However it seems that thermal runaway in a scientific sense doesn't necessarily equate to a _complete_ runaway. To get the cells into runaway, they had to be overcharged, with a high current sustained to them, and at the same time have an external heat applied to them. Which was done in a controlled way with an electric coil. They "ran-away" in the sense that a chemical reaction took place that then raised the temperature further, and after removing the charger and the external heat source the reaction continued and the cells did not cool down, but continued to melt.

Those conducting the experiments (Chemists or Physicists, I believe) deemed that to be thermal runaway, that the cells ran up to a higher temperature, and could not be "put-out" with normal measures, fire extinguisher, water, etc. Who am I to argue with scientists on the matter, but the temperature ultimately stabilized at a temperature just below that of what is required to ignite wood, but high enough to make it smolder. To a non-scientific person, that is not thermal runaway. There was no fire, just a very hot melted battery.

Anyway, I only bring this up because it is possible to find work that proves LFP can go into thermal runaway, and so there will always be that argument that it _can_ happen even if it is unlikely. I think it is important to understand what actually happens during that event and that thermal runaway with LFP doesn't equate to an uncontrollable fire. It is just a hot melted battery.

For sure, the safety of LFP is very well tested, lets not forget LFP are not new, but several decades old. A whole lot of science knowledge has been gained in that time. The only "issue" is that the media, and hence forth the public, can't differentiate between various lithium battery types.

This video shows otherwise and is a great o e to show people that are scared about thermal runaway with lifepo4
https://youtu.be/R9xZf4p8PkQ
It just doesn't happen period.

[wholybee]

Originally Posted by newhaul

This video shows otherwise and is a great o e to show people that are scared about thermal runaway with lifepo4
https://youtu.be/R9xZf4p8PkQ
It just doesn't happen period.

That is an older video, and doesn't really prove that thermal runaway can't happen, only that it didn't happen under the conditions of those tests.

If you read my post carefully, you note that thermal runaway with LFP is not hot enough to ignite wood that it is in contact with. Which is at odds with most people's definition of thermal runaway.

[s/v Jedi]

Again, it is not a thermal runaway. It is not an opinion, it is factually wrong.

A thermal runaway has an exothermic reaction, which feeds the chemical process.

For batteries, when you stop charging, they keep getting hotter all the way up to combustion.

LiFePO4 opens the pressure relief valve and gets hot, but not anywhere hot enough to combust anything aboard a boat.

See Wikipedia for explanation. LA batteries as well as Lithium-Cobalt batteries have thermal runaways.

[newhaul]

Originally Posted by wholybee

That is an older video, and doesn't really prove that thermal runaway can't happen, only that it didn't happen under the conditions of those tests.

If you read my post carefully, you note that thermal runaway with LFP is not hot enough to ignite wood that it is in contact with. Which is at odds with most people's definition of thermal runaway.

Your definition is not a thermal runaway.
https://dragonflyenergy.com/thermal-runaway/

Thermal runaway is a chain reaction within a battery cell that can be very difficult to stop once it has started. It occurs when the temperature inside a battery reaches the point that causes a chemical reaction to occur inside the battery. This chemical reaction produces even more heat, which drives the temperature higher, causing further chemical reactions that create more heat.

In thermal runaway, the battery cell temperature rises incredibly fast (milliseconds). The energy stored in that battery is released very suddenly. This chain reaction creates extremely high temperatures (around 752 degrees Fahrenheit / 400 degrees Celsius).

[wholybee]

Originally Posted by s/v Jedi

Again, it is not a thermal runaway. It is not an opinion, it is factually wrong.

A thermal runaway has an exothermic reaction, which feeds the chemical process.

For batteries, when you stop charging, they keep getting hotter all the way up to combustion.

LiFePO4 opens the pressure relief valve and gets hot, but not anywhere hot enough to combust anything aboard a boat.

See Wikipedia for explanation. LA batteries as well as Lithium-Cobalt batteries have thermal runaways.

Again, I am not disagreeing with you and that is what I always believed (and still do). But that is not what the research on LFP says. Runaway is being described a rise in temperature with a feedback loop as you describe where the heat from the reaction feeds back into it, but that reaction does not have to end in fire. There is a maximum temperature that is reached, after which it begins to cool.

Here is one such study, just one I found quickly, not as thorough as others I have read. It shows the temperature rising quickly (in this case to a temperature high enough to start a wood fire-which is new to me) and after reaching that temperature, quickly cooling back down. But the cells themselves don't burn.

The second stage is the thermal runaway stage. All battery temperatures are rising rapidly. The
starting temperatures of thermal runaway are 120 °C (25 Ah), 131 °C (60 Ah) and 116 °C (200 Ah). The
highest temperatures reached by thermal runaway are 263 °C (25 Ah), 514 °C (60 Ah) and 313 °C (200
Ah), respectively. It can be seen that the highest temperature of battery thermal runaway has nothing to
do with battery capacity.

https://iopscience.iop.org/article/1...1/1/012114/pdf