Monzilla - BURNED IN LIPO FIRE AUGUST 11

gwhy! said:
As I said before its irrelevant what chemistry you have it can all start a fire..
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Your assertion that all lithium-ion cells are equal with respect to safety considerations is simply not true. When making a battery choice, I encourage everyone to do so on the basis of forum-independent research. See for instance http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery#Safety
One important advantage over other lithium-ion chemistries is thermal and chemical stability, which improves battery safety.[6] LiFePO4 is an intrinsically safer cathode material than LiCoO2 and manganese spinel. The Fe-P-O bond is stronger than the Co-O bond, so that when abused, (short-circuited, overheated, etc.) the oxygen atoms are much harder to remove...

... As a result, lithium iron phosphate cells are much harder to ignite in the event of mishandling especially during charge, although any battery, once fully charged, can only dissipate overcharge energy as heat. Therefore failure of the battery through misuse is still possible. It is commonly accepted that LiFePO4 battery does not decompose at high temperatures.[6] The difference between LFP and the LiPo battery cells commonly used in the aeromodeling hobby is particularly notable.
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the last 2 post have totally missed the point.. :roll: it do not matter what chemistry you use .. battery fires can start for thousands of reasons and are very rarely related to chemistry. if you have a battery that can only deliver 1A max into a short and can dissipate the heat generated then this is going to be a much safer battery than a battery that can deliver 400A into a short that can't shift the heat .
 
gwhy! said:
the last 2 post have totally missed the point.. :roll: it do not matter what chemistry you use .. battery fires can start for thousands of reasons and are very rarely related to chemistry. if you have a battery that can only deliver 1A max into a short and can dissipate the heat generated then this is going to be a much safer battery than a battery that can deliver 400A into a short that can't shift the heat .
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Again, with all due respect, the fires we are discussing are NOT being caused by external shorts like dropping a wrench across terminals. It appears they are being caused by cell balance problems and most frequently in LiPO. Further it appears that this is much more common on this website with LiPO than any other chemistry. Given that most batteries used by members of this forum are likely LiFePO4 ,I think it is probable that the frequency of fire per installation of LiPO is much higher. If I am wrong, someone correct me.

If you go to the Fire entry on the forum Wiki, all of the examples are LiPO except one LiFePO4 that was thought to be a short external to the battery and one lead acid battery that was reported in a local news story.

If people want to use LiPO in an informed and appropriately careful way, go for it. I merely want to promulgate information about its relative safety. I don't sell any batteries so don't have a dog in the fight. But I think the evidence is pretty strong that LiPO presents a significantly higher risk of a battery fire based on empirical evidence on a per installation basis. I further think that saying all batteries can cause fires and so they are all equally dangerous is incorrect, potentially dangerous of itself, and flies in the face of both battery science and evidence.

If anyone has any actual research that indicates that lithium cobalt oxide batteries are no more frequently implicated in battery fires in the last couple of years or so than any other chemistry on a per installation basis then I'll be quiet. Otherwise, I am afraid eventually someone on this board is going to get killed in a battery fire and I am willing to bet it will involve LiPO and I am interested in helping prevent that.

Note that I posted my personal experience on Aug. 9th. On Aug. 11th, an ES member's house burnt to the ground for probably exactly the same reason I pointed out in my post that I had a battery fire. I am hopeful with enough postings, people will take proper precautions when experimenting with LiPO. If that gets your knickers in a twist, sorry about that.

Edit: Again, I have tremendous personal respect for GWHY. He is, not in small part, the reason why my first ebike was a mid-drive.
 
chroot's fire was caused by a short in the charging lead that ignited the plastic bag it was in. lifepo4, shorted

it appears that greg's fire was caused by a short because he was charging with a balancing charger. lipo, shorted

bike fanatic shorted one higher voltage lipo pack to a lower voltage lipo pack and it caught on fire. lipo, overcharged lower pack

floont was bulk charging lipo with no BMS or protection it appears. lipo, overcharged

those are the only ones i have seen here.

using a BMS can avoid overcharging and if the pack is shorted on the output it can shut off the current to prevent the cells from overheating and going into thermal runaway. it cannot avoid a fire caused by shorts on the charging leads as was the case in chroot's fire.

but with a BMS you can avoid over discharging your pack and it will balance the cells as the pack ages and the cells go farther and farther outa balance over time. this is true for both lipo, lithium ion, and for lifepo4. that is why no manufacturer sells batteries without a BMS.
 
But I think the evidence is pretty strong that LiPO presents a significantly higher risk of a battery fire based on empirical evidence on a per installation basis
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Bingo! Very well said. 95 % of ES members are not racers, like Zombiess, why else do you need 400 Amp discharge rate?
 
how do you know that the charger did not go short on its output in this instance ? or maybe a balance tap wire got shorted. I would speculate that nearly all battery related problems ( no matter what chemistry it is ) are related to wiring\bms\charger problems .
 
the problem is that everyone speculates and nobody uses the available data. i know of only the four fires.

since there are so many people with their own opinion they think is most important then it is kinda pointless to even discuss it.

if you have evidence of how a fire started separate from these then it would be useful to add but just opinions don't matter much in reality.

i do know that lipo can be overcharged to 4.4V without igniting because i have seen lipo puffers at 4.4V, but i am not sure how to keep it from igniting when overcharged so i operate on the assumption that any lipo cell over 4.3V is liable to ignite if the charging current is 1C or higher..
 
dnmun said:
there are a lot of self righteous people on this board who make it a point to say that using a BMS is stupid.
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This is not the thread for BMS. That said, YOU ARE STUPID for using BMSes that don't work. How many times do you need to be insulted?
 
dnmun said:
the problem is that everyone speculates and nobody uses the available data. i know of only the four fires.

since there are so many people with their own opinion they think is most important then it is kinda pointless to even discuss it.

if you have evidence of how a fire started separate from these then it would be useful to add but just opinions don't matter much in reality.
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I agree with you but personally I don't think this information is going to be possible to gather.

If you do something that implies you were careless and did not heed sage advice, you are unlikely to say so. Because if you do, someone will eventually imply you are an idiot (see recent threads). This may have liability implications as well. The easiest thing to do is to blame it on something over which you did not have control.

There are at least two additional examples on the "Fire" entry in the Wiki. Looks like bulk charging cells that are likley out of balance is a common thread in at least three cases. Also, it is known that LiPO has a lower decomp. temp. That is enough for me, having seen one. I know from personal experience LiPO is not for me. To each his own.
 
As stated before, I will never use LiPo again.

There are safer chemistries that have marginally lower energy densities. I will go back to gold ole' Lead Acid while I investigate what I need for using LiFePo in the future.

FA
 
Ypedal said:
ok. all that aside...

Floont, got a paypal address we can send donations to ? ... not very rich these days but i will dish out a few and i'm sure others will as well...

Is your insurance going to cover things ?.. anything to share in that regard ?
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I thank you with all of my heart, but insurance is taking care of everything. Thanks, again!

FA
 
Floont, I'm glad your insurance covers the damages.

All batteries can burn, the problem is LiPo's burn at a much more prodigious rate. I can't imagine how one could even put out a 15ahr pack. They feed on each other and don't stop until all the electrolytes burn off. There is a reason why you don't see car manufacture or even bicycle manufacture ever use such an unsafe chemistry. Those who think they know better than industry are only fooling themselves. If you play with fire, plan to get burned. Even though I use them, I could never recommend them.
 
arkmundi
your quote is spot on on comparison of different cell chemistries if it comes to safety.
To ignite other chemistries is much more difficult than LiPolymer - that is absolute clear .
I agree with pdf, arkmundi , kfong.
Very good point, electronics, namely BMS fail , especially cheap POC.
 
I know Hebb ebikes used Lipo in some of their batteries. Had a BMS, 10ah lipo pouches.

I've seen some others too. Usually low c rate cheap stuff.
 
veloman said:
I know Hebb ebikes used Lipo in some of their batteries. Had a BMS, 10ah lipo pouches.

I've seen some others too. Usually low c rate cheap stuff.
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According to their website, Hebb is using lithium manganese oxide, NOT lithium cobalt oxide. Lithium manganese oxide decomposes at 265 deg C, lithium cobalt oxide at 150 deg C. Lithium manganese has a reputation as one of the safest lithium chemistries and is used by several of the more reputable e-vehicle businesses.
 
The real problem is "thermal runaway" and I'm sure many factors lend to that, including the ones fore-mentioned: battery chemistry, make of the cells, chargers, charge/discharge history & especially over-charging for lack of sufficient protection. But one thing not mentioned is pack design & build. I was reading that all the marketable electric automobiles, like the Tesla S and Chevy Volt, compartmentalize their cells to prevent thermal runaway. They do that so if one cell goes, its just that one cell, that it can't spread to the surrounding cells. Anyway, the dialog is certainly making me rethink my approach to the question of pack design!

Floont, its good to hear your progress in recovery from this disaster!
 
pdf said:
veloman said:
I know Hebb ebikes used Lipo in some of their batteries. Had a BMS, 10ah lipo pouches.

I've seen some others too. Usually low c rate cheap stuff.
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According to their website, Hebb is using lithium manganese oxide, NOT lithium cobalt oxide. Lithium manganese oxide decomposes at 265 deg C, lithium cobalt oxide at 150 deg C. Lithium manganese has a reputation as one of the safest lithium chemistries and is used by several of the more reputable e-vehicle businesses.
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This was from a bike that was at least 3 years old. It said lithium polymer on it when I opened it up.
 
veloman said:
pdf said:
veloman said:
I know Hebb ebikes used Lipo in some of their batteries. Had a BMS, 10ah lipo pouches.

I've seen some others too. Usually low c rate cheap stuff.
Click to expand...

According to their website, Hebb is using lithium manganese oxide, NOT lithium cobalt oxide. Lithium manganese oxide decomposes at 265 deg C, lithium cobalt oxide at 150 deg C. Lithium manganese has a reputation as one of the safest lithium chemistries and is used by several of the more reputable e-vehicle businesses.
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This was from a bike that was at least 3 years old. It said lithium polymer on it when I opened it up.
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Lithium polymer is a generic term that refers to the fact that it uses a polymer electrolyte which is true of nearly all secondary lithium batteries (that is, lithium ion batteries). In this sense, we are nearly all using lithium polymer batteries.

EDIT: "LiPo" is generally used on this forum to mean RC lithium cobalt oxide. Even then, all lithium cobalt oxide batteries are not the same (they can have different cathode treatments designed to partially passivate it, I believe), so it is confusing. My contention is that chemistry matters as well as battery maintenance. I can only say for certain that lipo batteries have a lower decomposition temperature than any other lithium chemistry. I can also say from experience that a badly balanced Lipo battery can catch on fire when bulk charged. I further suspect that RC Lipo is more subject to failure after electrical and possibly mechanical abuse than other chemistries, but finding rigorous studies on RC Lipo is difficult. It's widespread use in vehicle power is fairly new and as a battery for hobby aircraft, it was not much on anyone's radar.
 
dnmun said:
no, limn2o4 is lithium ion becasue it uses an electrode/separator sandwich with liquid electrolyte and does not have the solid polymer electrolyte.
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Hebb calls their battery a "lithium polymer battery" and a "lithium manganese oxide" battery in two different places in their literature. I had not heard of the company before today so I am not sure what their battery construction is. I doubt it is the same chemistry and cathode design as RC Lipo, but I do not know that.

My understanding is that "lithium ion" merely refers to the use of secondary (non-metallic) lithium. That is, all consumer "lithium polymer" batteries are also lithium ion batteries.
 
pdf said:
dnmun said:
My understanding is that "lithium ion" merely refers to the use of secondary (non-metallic) lithium. That is, all consumer "lithium polymer" batteries are also lithium ion batteries.
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Yes, my understanding too. Lithium-ion is the broad class, of which LiPo and LiFe are distinct types. The construction details, cathode & anode, electrolyte, format, packaging & seals are all unique to the manufacturer and should be looked at in detail before making a purchase decision. The "polymer" in LiPo means the electrolyte. There are other ways to make electron's flow.
 
that was a cheap trick. i never said the things you sneaked into that quote. not sure what you are trying to do by making up stuff but i will repeat.

the lipo is a sandwich of an organic polymer attached in layers to the elctrodes and it has no liquid electrolyte.

the lithium ion pouches use a liquid electrolyte and a cathodic matrix for the limn2o4.
 
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