Alan B
100 GW
Fuses or fusible links are recommended. Best within a few inches of the battery, part of the series/parallel harness.
LiPo explosion !!!
- Thread starter HAL9000v2.0
- Start date
jonescg
100 MW
While petrol is highly flammable, and explosive under the right conditions, it's not like there is a spark plug located directly above the pool of fuel. However, that's essentially what we have on big battery packs. Fusable links between packs is a good idea, but even better if these fuses were somehow physically separated from the main cell body, so as to limit any potential ignition of electrolyte.
And I'm with DocBass, you gotta have a simple charging system. The less frocking around with positives and negatives the better!
And I'm with DocBass, you gotta have a simple charging system. The less frocking around with positives and negatives the better!
theRealFury
10 kW
Batteries are like anything else in this world, dangerous in the wrong hands but if you have a brain and take precautions then you minimise the risks. Even a bucket of water is lethal to the right idiot that wants to stick his head in it and try to breath. But we don’t see any posts saying "OMG!!! (Insert random name here) drowned in a bucket of water, makes me want to never get washed again!!!" Honestly if you’re so scared of batteries then you really shouldn’t be playing with EV's.
Random facts, Lipo cells have 25% of the potential of dynamite, so for every KG of Lipo you have you’re basically carrying around 250g of dynamite. 1KG of dynamite has 7.5MJ of potential where as 1 US gallon of gasoline has 132 MJ of potential.
It doesn’t take a genius to work out just how much more dangerous petrol or gas is than Lipo batteries, yet we have had petrol/gas tanks in automobiles for over 100 years.
Random facts, Lipo cells have 25% of the potential of dynamite, so for every KG of Lipo you have you’re basically carrying around 250g of dynamite. 1KG of dynamite has 7.5MJ of potential where as 1 US gallon of gasoline has 132 MJ of potential.
It doesn’t take a genius to work out just how much more dangerous petrol or gas is than Lipo batteries, yet we have had petrol/gas tanks in automobiles for over 100 years.
TylerDurden
100 GW
It appears for LiPo, "best-practices" are still evolving, let alone well-observed.
I'm confident that events with gasoline are so common that they don't qualify as newsworthy (other than traffic-nuisance or failblog).
I'm confident that events with gasoline are so common that they don't qualify as newsworthy (other than traffic-nuisance or failblog).
dogman dan
1 PW
I'm not sure what kind of lipo that was in the fire at the race. My turnigy's have popped tabs quite quickly.
Meanwhile, I keep em like this.
Meanwhile, I keep em like this.
oatnet
1 MW
theRealFury said:
You can minimize the risks for an EXTERNAL short, but you can't do squat about the risks from an INTERNAL short. Further, once either short is introduced, a chemistry prone to thermal runaway will catch and combust, wheras an inert cathode will not. The only way to minimize that risk is to use a chemistry with an inert cathode.
Finally, I don't care how smart you are or how much you minimize the risks, when you finish that race build at 4:00am you still might plug that connector in backwards. This thread shows what happens when you do that with lipo... With LiFe, I've blown off connectors doing this, I've melted balance wires together, and in every case when the short was removed, the cells did NOT proceed to thermal runaway. I've had internal shorts in cheap chinese LiFe Prisimatics, the cell gets warm and puffs up and goes to 0v - but it does NOT proceed to thermal runaway. I've run quality LiFe Prisimitics flat due to my own stupidity, the cells get warm and puff up and go to 0v - but they do NOT proceed to thermal runaway. So there is an additional, separate risk when you run a chemistry that is prone to thermal runaway. The ONLY way to effectively manage that risk is to minimize its scope of impact - IE make sure your bike is the only thing that burns.
theRealFury said:
The difference being that professionals at a factory are engineering, testing, and manufacturing the gas tanks, wheras for many folks the battery packs are their first amateur builds.
In addition, we have 100 years of research on how to build gas tanks for cars, and with all that research, we still had folks killed by exploding gas tanks in their Ford Pintos, and 14 years of GM trucks. E:S has 2-3 years building 2nd gen LiPo battery packs, and noobs may only have hours. Not a reasonable comparison.
-JD
vanilla ice
1 MW
Yeah up until like a month back I thought I was too slick to hook up my lipo connectors wrong.. right up until I did it when I was tired. When I went to yank the connectors apart I could feel the current in my hands right thru the insulation..
Eventually you will hook stuff up wrong.
Eventually you will hook stuff up wrong.
theRealFury
10 kW
oatnet said:
Well no offence Oatnet but I would have to argue that unfortunately I’m smart enough to use a connector that cannot be connected the wrong way round. Just a little outside the box thinking can minimise or remove risks that you are classing as unavoidable.
oatnet said:
The reason I brought fuel tanks up was a counter to the argument that batteries are not safe enough to be installed into an EV. Now if you’re going to take some "home made battery packs" and cram them into an EV then perhaps you are asking for trouble. But the professionals at the factory that build the EV's are the same type of professionals that build the fuel tanks so your argument is a moot point there I’m afraid.
At the end of the day batteries really are not as dangerous as fuel in a tank and we have learned to live and work with fuel in tanks for a long time, saying we shouldn’t use batteries that can enter thermal runaway is like saying that we shouldn’t use fuel that burns in air. I never once said that batteries were safe, I merely said that they can be just as safe as a tank of fuel if you take the correct precautions.
dnmun
1 PW
but you don't take proper precautions. you just think you do.
you will not be able to take your battery out of your apartment after it catches on fire, you just think you can.
JD was polite enuff to explain to you why the chemistry of the anode is so important. but you think you know more than he does.
i don't think so.
people need to be aware they can and will be indicted for negligence and possibly for arson if they burn down their apartment building. it doesn't matter how cool and smart you think you are. you will be sued and all the money you make for the remainder of your life will be paid to cover the damages.
you will not be able to take your battery out of your apartment after it catches on fire, you just think you can.
JD was polite enuff to explain to you why the chemistry of the anode is so important. but you think you know more than he does.
i don't think so.
people need to be aware they can and will be indicted for negligence and possibly for arson if they burn down their apartment building. it doesn't matter how cool and smart you think you are. you will be sued and all the money you make for the remainder of your life will be paid to cover the damages.
theRealFury
10 kW
Who said anything about me buring down my apartment building... i take precautions like the rest of you... my lipo is sat on my balcony on a concrete floor thats over 12inch thick and about 8 feet from anything remotely flammable, i dont store it in my basement or garage or on my computer desk like a lot of people do.
As to the reast of your post, ill just leave it where it lies... dont intend to start an argument on these forums, was just getting my feelings and views accross and trying to knock back the argument that batteries are not safe for EV's.
As to the reast of your post, ill just leave it where it lies... dont intend to start an argument on these forums, was just getting my feelings and views accross and trying to knock back the argument that batteries are not safe for EV's.
oatnet
1 MW
theRealFury said:
If that is what you got from my post, I think you missed this part of my comment: "The ONLY way to effectively manage that risk is to minimize its scope of impact - IE make sure your bike is the only thing that burns."
A number of folks (dogman comes to mind) effectively manage the risks of LiPo. If my house, and work parking, had a safe place to store and charge a LiPo build, I would probably risk using LiPo on some builds. A lot of folks come here, read the lipo fanboy posts, and put it on a bike so it is light enough to carry up to their apartment... Not enough do the ABC's:
A) What is the worst place for my bike to go up in flames
B) What would I do if it caught fire there
C) What would happen if it caught fire there, and I was out?
D) What will happen to me, and the eBike hobby, if I burn my apartment building down and people die?
The thing that drives me nuts about the LiPo vs Life arguments is folks who say one chemistry is superior to the other. I think that LiPo's are ideal for a number of applications, LiFePO4 is ideal for another set of applications, NiCD/NiMH/SLA even have their ideal uses, each superior for THAT APPLICATION. I can see how LiPo rocks for a number of people, why can't they see that LiFe rocks for my needs?
-JD
liveforphysics
100 TW
oatnet said:
Yes, it's a fact, these things really happen. I exploded our 12kw TTXGP bike charger at 2am plugging it in backwards... AFTER JUST CHECKING IT WITH MY METER.... Evidently, I checked it with the meter just to confirm it was indeed reverse polarity... lol
Fortunately every plugging-in related mistake with LiPo that I've had has been fortunate enough to instantly vaporize the connector (even SB120's and SB180's) and the LiPo never even got warm. That doesn't mean in a situation with thinner wires or weaker packs that it couldn't weld the circuit closed and end up blowing up. But... I've also had headways cells vent billowing flames in extreme short situations as well, about 90% of the time they just pop the little tabs inside the can harmlessly, just like RC LiPo packs do, but a low cell can't always pop the tabs, they reverse, get extremely hot, start venting boiling solvents, then ignite and make a little 3-4ft flame blasting thing for about 2-3minutes continuously... And that's LiFePO4...
SamTexas
1 MW
Agreed. But why do you care if others approve or disapprove your battery chemistry choice? You are the only person that matters.oatnet said:
kfong
100 kW
That's a poor attitude Sam; many people come onto these forums looking for information and to make informed decisions. Oatnet has presented a good argument as to why Lipo's should be respected as well the use of other safer chemistries. I’ve only started to use lipos this year for ebikes, even though I’ve been using them for years on my RC stuff. That much energy stored can’t be taken lightly. I’ve had my own lipo fire and it’s not something I want to repeat. I’ve found a charger that I trust, and do as much as I can to minimize any accidents. I still won’t recommend the use of these to my friends unless they are willing to take all the necessary steps to keep a fire from happening. I have no problem setting up A123 or Konions for my 2 nieces ages 10 and 13 on their scooters and on an ebike for one of my friends recently with Konions. Lipo’s to me are still not ebike ready. Even Opti and most ebike manufacures have avoided Lipos, at least I have not seen any being offered yet in the consumer market for ebikes, but I could be wrong. Just the liability alone would suggest otherwise.
SamTexas
1 MW
Huh? What the heck did I say that made it bad?kfong said:
theRealFury
10 kW
oatnet said:
Sorry Oatnet, i think we just had a missunderstanding here, i should perhaps have quoted what i was countering but i didnt because i thought i would put my views out to everyone and not just aim a reply at the poster... but below is the actual post that made me bring it up, which isnt yours im afraid.
zEEz said:those kind of happenings makes me often to rethink about my hopes about future mobility ....
I mean .... are you sure your highest hope is to have 400x A123 flat pouch cells under your ass
in your future auto? ... Perhaps LiFe are not exploding, flaming or venting, but hey
No dub petrol is flammable, but chemical energy stored in batteries is kind of weird too ... 8)
I suppose some nice breakthroughs are still needed in this technology to get safe e-autos ...
have fun!
megacycle
100 kW
What's the problem we've all got MSDS sheets for our batteries so we know what we are dealing with, got the safety control measures in place, first aid is up to date and sat the electrical exam certifying us to build battery systems in countries where it is required and keeping all records and all pigs are flying :wink:
zEEz
1 kW
theRealFury said:Sorry Oatnet, i think we just had a missunderstanding here, i should perhaps have quoted what i was countering but i didnt because i thought i would put my views out to everyone and not just aim a reply at the poster... but below is the actual post that made me bring it up, which isnt yours im afraid.
zEEz said:those kind of happenings makes me often to rethink about my hopes about future mobility ....
I mean .... are you sure your highest hope is to have 400x A123 flat pouch cells under your ass
in your future auto? ... Perhaps LiFe are not exploding, flaming or venting, but hey
No dub petrol is flammable, but chemical energy stored in batteries is kind of weird too ... 8)
I suppose some nice breakthroughs are still needed in this technology to get safe e-autos ...
have fun!
Hi, fury and all there!
Now I understand the business of the petrol tank ...
and the fact that I was the only responsible for the semi-flame ...
Sorry if I didn't explain my views clearly, perhaps if I was quoted earlier I could have had it rectified earlier:
How I see the story is that:
-LiFe are great because they have no thermal runaway but to fit an automotive application I would require a
very well designed box around them if they are in pouch form and not like Thundersky or CALB ....
-LiPO is dangerous at the moment ... thermal runaway started even from poisoning and defects is not
an option for a mass produced car, at least to my eyes ...
NEVERTHELESS, if the LiPO producer are adopting in short time -can be as short as one or two years-
in their new production cells the NEW PLASTIC ELECTRODE SEPARATOR that is changing
to impermeable in case of thermal runaway I WOULD ACCEPT THEM AS WELL ... 8)
Those are my hopes ... since I would really love to get hold of some tons of intrinsically
safe rechargeable batteries in order to electrify my motorbike and my car ....
but for me the actual LiPO are not up to the task ... LiFe yes, but I would like lower prices
have fun!
dnmun
1 PW
this is totally so far out it doesn't even make sense.
i commented early on that people should recognize that lipo will burn when overcharged so they need to be safe by charging in a safe place where in the event of fire, the building is not ignited. seemed pretty simple to try to explain to people that the risk of being indicted was high since everyone knows this can happen to lipo, and the DA would make you say that on the witness stand, or he would find others to testify. this is what the DA does for a living, and to get reelected.
then it went berserk on some other tangent, and then JD explained to him that the chemistry is important since lifepo4 does not have this problem of thermal runaway that lipo does, then he trashed JD.
i explained why he was not being in safe in spite of himself because the lipo pouches can not be handled once they are on fire. in fact the pressure inside the bags will cause them to explode like napalm, which you can see in the picture that the OP had posted.
thermal runaway is initiated when the lipo is charged beyond the 4.2V range for long enuff to cause the cell to finally break. it is thought that what happens is that part of the anode surface breaks off under this overvolting stress, exposing new surface area, and this creates a huge exothermic reaction which causes the rest of the anode surface to continued breaking off as the cell goes into a positive feedback state called thermal runaway. this cannot be stopped, it continues until the cell has burned out, fire extinguishers or foam will not stop it. with these mylar pouches the polymer ignites and burns in the atmosphere since it is not contained in a metal cylinder.
this does not happen to lifepo4. the oxygen in the lifepo4 is locked into a crystalline lattice that holds it until the lattice is heated to over 600o C. the lipo releases the oxygen in the organic polymer that holds the cathodic structure, this is what burns and creates the fire.
that is why lifepo4 is safe and lipo is not. this is why apartment managers and building supervisors will outlaw ebikes from the premises, because of the demands of the insurance companies. that is why it is important in spite of how self righteously overconfidence of how great you are in being safe. do you even have a shovel to pick it up and throw it in the bathtub in your apartment??? do you have dikes to cut the cable holding it to the charger or the bike? or can you get the bike outside while it is on fire???
i never said anything about whether people should use lipo or not, just most people do not even recognize the risks or where the risk is. i was trying to help overcome that lack of foresite, in order to prevent a tragic accident from leading to the abolition of charging or even storage of ebikes in public buildings. but i fear it is a lost cause. one day an assistant DA will be holding this thread up for the jury to read, imo.
i commented early on that people should recognize that lipo will burn when overcharged so they need to be safe by charging in a safe place where in the event of fire, the building is not ignited. seemed pretty simple to try to explain to people that the risk of being indicted was high since everyone knows this can happen to lipo, and the DA would make you say that on the witness stand, or he would find others to testify. this is what the DA does for a living, and to get reelected.
then it went berserk on some other tangent, and then JD explained to him that the chemistry is important since lifepo4 does not have this problem of thermal runaway that lipo does, then he trashed JD.
i explained why he was not being in safe in spite of himself because the lipo pouches can not be handled once they are on fire. in fact the pressure inside the bags will cause them to explode like napalm, which you can see in the picture that the OP had posted.
thermal runaway is initiated when the lipo is charged beyond the 4.2V range for long enuff to cause the cell to finally break. it is thought that what happens is that part of the anode surface breaks off under this overvolting stress, exposing new surface area, and this creates a huge exothermic reaction which causes the rest of the anode surface to continued breaking off as the cell goes into a positive feedback state called thermal runaway. this cannot be stopped, it continues until the cell has burned out, fire extinguishers or foam will not stop it. with these mylar pouches the polymer ignites and burns in the atmosphere since it is not contained in a metal cylinder.
this does not happen to lifepo4. the oxygen in the lifepo4 is locked into a crystalline lattice that holds it until the lattice is heated to over 600o C. the lipo releases the oxygen in the organic polymer that holds the cathodic structure, this is what burns and creates the fire.
that is why lifepo4 is safe and lipo is not. this is why apartment managers and building supervisors will outlaw ebikes from the premises, because of the demands of the insurance companies. that is why it is important in spite of how self righteously overconfidence of how great you are in being safe. do you even have a shovel to pick it up and throw it in the bathtub in your apartment??? do you have dikes to cut the cable holding it to the charger or the bike? or can you get the bike outside while it is on fire???
i never said anything about whether people should use lipo or not, just most people do not even recognize the risks or where the risk is. i was trying to help overcome that lack of foresite, in order to prevent a tragic accident from leading to the abolition of charging or even storage of ebikes in public buildings. but i fear it is a lost cause. one day an assistant DA will be holding this thread up for the jury to read, imo.
zEEz
1 kW
dnmun said:
... ME, for example
have fun! (not with LiPO inside apartment
)
Alan B
100 GW
Life (and law) is not that simple.
There's enough Lipo in your house to burn it down already. At least in most houses.
It is how it is treated that makes it hazardous. Hooking it up wrong. Overcharging. Puncturing. etc.
There's enough Lipo in your house to burn it down already. At least in most houses.
It is how it is treated that makes it hazardous. Hooking it up wrong. Overcharging. Puncturing. etc.
I just saw this on Reddit this afternoon. Someone triggered a car-killing battery fire by short-circuiting lead-acid batteries together during a jump.
http://imgur.com/a/JSntv
Batteries have their risks just like anything else in life. Its just a matter of managing that risk. Just the same, the discussion thread has a lot of clueless people wondering what/how/why a fire was the result.
http://imgur.com/a/JSntv
Batteries have their risks just like anything else in life. Its just a matter of managing that risk. Just the same, the discussion thread has a lot of clueless people wondering what/how/why a fire was the result.
zEEz
1 kW
Alan B said:
While this is a fair truth, I still have to witness a LiPO or LiION fire in the wild ...
Perhaps it is because of overcautious smart battery systems in the average
consumer equipment, or perhaps it is because the quality control on those
battery is better ... or perhaps it is just plain LUCK
I can testimony this: I mistreated either Laptop and Mobile phone LiBattery ...
but the worst thing I got till now it is the funky sweet smell the battery has
released in the air ... toxic perhaps ... but that's it .... overpressure
released in the air via the safe valve .... no FIRE no Explosion ...
PS. I keep my RC LiPO inside the house but in a ceramic vase ...
have fun!
dnmun
1 PW
i had one of the sony laptops catch on fire at my house here. one of the tenants was charging the laptop and left it on the bed, smothered in the comforters and it caught the comforter and mattress on fire. the flames were 4' high when i entered the room to put out the fire, but nothing else caught on fire, it had not reached the curtains.
those were cylindrical laptop lipo, they themselves did not ignite, just burned red hot like homer simpson's uranium nugget. the battery had melted through the plastic case and when i picked up the bed to move everything outside, the cell slid out of the laptop case and onto the carpet. melted a hole through carpet immediately and was burning through the pad when we doused it with water. picked it with woodstove shovel and when i carried the bed out across the porch, the other cell slid out and burned a hole in the carpet on the porch before i kicked it outside on the ground.
those were the little 3200mAh laptop packs, but i think the metal sleeve is what kept my house from total loss, if it had been pouches like these that we are talking about, i think the fire would have spread much faster. i also want to note that a tenant was upstairs sleeping during the entire fire, with the smoke alarms blaring so loud that i could hear them from outside. since his grandfather was a former state senator, they woulda sued my ass off and woulda spent even more money on lawyers than the mercedes coupe they gave him for a gift, i woulda lost everything in the lawsuit over his death if that had been the case.
so been there, done that.
those were cylindrical laptop lipo, they themselves did not ignite, just burned red hot like homer simpson's uranium nugget. the battery had melted through the plastic case and when i picked up the bed to move everything outside, the cell slid out of the laptop case and onto the carpet. melted a hole through carpet immediately and was burning through the pad when we doused it with water. picked it with woodstove shovel and when i carried the bed out across the porch, the other cell slid out and burned a hole in the carpet on the porch before i kicked it outside on the ground.
those were the little 3200mAh laptop packs, but i think the metal sleeve is what kept my house from total loss, if it had been pouches like these that we are talking about, i think the fire would have spread much faster. i also want to note that a tenant was upstairs sleeping during the entire fire, with the smoke alarms blaring so loud that i could hear them from outside. since his grandfather was a former state senator, they woulda sued my ass off and woulda spent even more money on lawyers than the mercedes coupe they gave him for a gift, i woulda lost everything in the lawsuit over his death if that had been the case.
so been there, done that.
