Can you de-bloat XUBA 280aH Lifepo4 cell?
- Thread starter heirloom hamlet
- Start date
heirloom hamlet
life my way
4.8v
heirloom hamlet
life my way
Nailed it dude. Wish we'd discussed this at 8am.
heirloom hamlet
life my way
There was no monitoring that could be done to change this. It charged and rested based on the recourses writeup on the forum...minus the BMS. It was at the same voltage as the rest 3.55v. The charger was turned on to charge to 29.2... 3 minutes later the damage was done. It's just a dumb and unnecessary thing. The BMS is the only thing that could have prevented it other than not doing it...and the nightmare of selecting and using a BMS is its own huge topic.
heirloom hamlet
life my way
Yep, I tried to be that guy too. Lots of prep and learn time. Unfortunately, it takes a second to undo that. My advice, get your awesome new cells like I did, put them in parallel for a little while, connect them to your SCC and PV and enjoy.
Don't geek out and complicate what can be a pretty simple thing.
heirloom hamlet
life my way
The issue is what happened this morning. Essentially the cells all arrived within .002v of each other. And then the PV charge almost instantly irons that out to .001 or nothing.
heirloom hamlet
life my way
Charging up even cell by cell with that charger won't take a day, it'll take weeks...per cell. Not necessary. Start charging PV and start using nature's energy.
heirloom hamlet
life my way
I think the idea is you push them to new heights, like if you max bench 225lbs, you always will unless you show yourself more. But these are batteries, not human bodies, and I don't think it applies.
Others say they have no memory, too dumb. I tend to agree. They charge and last amazingly regardless of the top balancing. Balance wherever they are at in parallel so they have the same starting point and use them. I mean even that may not be necessary depending on what you get. Of my 32, I think 28 were within .001 off the boat and the others weren't far away. It takes no effort, works, and is 100 percent harmless.
heirloom hamlet
life my way
If you don't mind me asking, what was freight on just 2? I have a couple in the cart, but am waiting to hear if "Amy" responds to my inquiry first.
Even better would be if anyone on the forum ordered some extras and wanted to sell a couple.
When the cell was initial charged its capacity has been set. It may rise a small amount over the first few cycles as channels form in the anode? At least that's my understanding. Charging the cell up to 3.6V is acceptable to top balance. But that's all it is, syncing the cells to 100% manually. There is no reason to ever exceed 3.65Vpc, as at that point there aren't any ions left over in the anode.
The bench top balance procedure I posted above is the best way if the cells don't arrive balanced. Remember. This is with the cells in parallel, or a single cell. Charging in series like this without a BMS can cause the first cell to reach 100% to experience an over voltage event.
Some LFP cells will show a bit of memory after expended partial cycling below 80-90% SOC. But this memory is rarely a problem unless your charge termination current or voltage is especially low. This memory manifests as the current tapering a bit earlier. Continuing a CV charge until the current rises then falls will remove the memory effects impact on the charge curve. Since most passive balancing BMS need a minimum cell voltage to balance these types of effects are probably rarely seen in the wild. Though if you are only charging to 13.8V, and use a current termination (low 90s SOC?) then you might see this affect causing the top SOC level at termination drift down gradually over a 100 cycles or so. Its pretty dependent on the specific cell and temperature from the lab testing I reviewed.
The bench top balance procedure I posted above is the best way if the cells don't arrive balanced. Remember. This is with the cells in parallel, or a single cell. Charging in series like this without a BMS can cause the first cell to reach 100% to experience an over voltage event.
Some LFP cells will show a bit of memory after expended partial cycling below 80-90% SOC. But this memory is rarely a problem unless your charge termination current or voltage is especially low. This memory manifests as the current tapering a bit earlier. Continuing a CV charge until the current rises then falls will remove the memory effects impact on the charge curve. Since most passive balancing BMS need a minimum cell voltage to balance these types of effects are probably rarely seen in the wild. Though if you are only charging to 13.8V, and use a current termination (low 90s SOC?) then you might see this affect causing the top SOC level at termination drift down gradually over a 100 cycles or so. Its pretty dependent on the specific cell and temperature from the lab testing I reviewed.
newbostonconst
Solar Enthusiast
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I ordered a couple 90ah cells also but I think for just 2 280ah cells shipping would have been $49 to Michigan.
Ampster
Renewable Energy Hobbyist
Change what? That your cell got bloated? Maybe it was a bad cell. Or if it was a runner and going above 4.0, monitoring may have informed the monitoree to unplug and drain it before it got bloated..
Mathematically that would be what one would hope but it sounds like that cell was a runner and spiked a high voltage while the others were probably at less than 3.55 volts. Yes the average was 3.55 but every cell was not 3.55.
Yes, it can happen fast. The chemical reaction may have started earlier. Unless we have fctual data, it is just a hypothesis. There is one way you could have prevented it and that is by measuring the volt of each cell as soon as you turned on the charger to 29.2 or 3.65 per cell. An observation of each cell voltage before turning on the charger might have revealed danger was on the horizon.
Ampster
Renewable Energy Hobbyist
Having probably expressed such an opinion my feeling WAS that unless the cells are in the knees, the voltage in the middle is not very useful. However based on the instances of top balancing going wrong with no plausible explanation I am seeing some value in using an active balancer.
If noting else the voltage monitoring alone would give the user valuablevdata that was not available or reliable in those bloating cases.
Why active?
Doesn’t passive offer all the same benefits with a simpler system just at the cost of a tiny bit of wasted power??
I would point to the source I posted above. Do not top balance a pack in series without a BMS unless you are unfailingly vigilant/attentive. Looking away for more than a couple minutes can lead to trashed cells. Personally I would not use this method, and would charge cells in parallel or individually if top balancing was called for. In this case BMS means at a minimum: Cell voltage monitoring with a disconnect (or alarm if doing a bench test).
A note for newbs:
Average/calculated cell voltages derived from total pack voltages are not the same as actual/measured cell voltages. When in the knee a few percent capacity drift can cause one cell to spike into the damage zone. Do not assume that cell voltages are okay just because the pack voltage is within tolerance.
For example, if you are charging 8x cells to 29.2V (3.65Vpc). Lets say all the cells are showing balanced at 3.55Vpc, so 28.4V However one cell is slightly more full. That cell will hit full while the others are sitting around 3.55V still. So that cell with spike within minutes to 29.2 -(3.55*7) = 4.35V. Now the cell is damaged within minutes. If a person is extremely attentive, they can catch a cell spiking, and shut the charger down, but it only takes a short loss of attention. Too risky for me to do so without BMS. Now the other cells may only be passing an amp or two of current, so a passive BMS could shunt power around the high cell starting at 3.5Vpc, which gives the lower cells time to catch up. In this case the pack gracefully reaches the chargers voltage setpoint with all cells around the desired 3.65Vpc.
A note for newbs:
Average/calculated cell voltages derived from total pack voltages are not the same as actual/measured cell voltages. When in the knee a few percent capacity drift can cause one cell to spike into the damage zone. Do not assume that cell voltages are okay just because the pack voltage is within tolerance.
For example, if you are charging 8x cells to 29.2V (3.65Vpc). Lets say all the cells are showing balanced at 3.55Vpc, so 28.4V However one cell is slightly more full. That cell will hit full while the others are sitting around 3.55V still. So that cell with spike within minutes to 29.2 -(3.55*7) = 4.35V. Now the cell is damaged within minutes. If a person is extremely attentive, they can catch a cell spiking, and shut the charger down, but it only takes a short loss of attention. Too risky for me to do so without BMS. Now the other cells may only be passing an amp or two of current, so a passive BMS could shunt power around the high cell starting at 3.5Vpc, which gives the lower cells time to catch up. In this case the pack gracefully reaches the chargers voltage setpoint with all cells around the desired 3.65Vpc.
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thank you for sharing your experience as it s a frustrating situation but it s worth a lot to other like me to learn. I put my set of 4 battery in the solar system and will let the BMS do the work over the next few weeks. Seems like they are getting closer and closer daily. But i think my impression of this is... a BMS is essential and such a peace of mind.
heirloom hamlet
life my way
Yes series. This was a way to get the charge up to respectable levels before a switch to parallel for top balancing. To charge these 280aH cells in parallel at 5v would take a year.
Do you mean 5A? Cause 5V is bad mojo...
my understanding
-if charging in series, you absolutly need a BMS for saftey.
-If charging in paralele, very safe if set a 3.6v but can take a few days or a week. so do not be in a rush.
i left mine resting for 4 weeks in paralele and now in series with bms and it seems to get closer and closer every charge cycle.
heirloom hamlet
life my way
Lol. Yes, of course.
Hi Luthj
Can I ask ......... where you sourced your 12X280AH batteries?
What was the cost (total, per cell in USD$)?
How much for shipping and was it to the USA?
How long did it take.
On your replacements did you purchase from the original supplier?
How did the replacement prices and shipping costs compare per cell to the original 16?
Did you try at all to suggest the cell was defective and ask for compensation-if so how did they respond?
How was your experience overall with the supplier?
Ya, lots of questions.....but I am about to do what you did.......but hopefully.........without the bloating part.....
I appreciate your share so we can all learn.
Can I ask ......... where you sourced your 12X280AH batteries?
What was the cost (total, per cell in USD$)?
How much for shipping and was it to the USA?
How long did it take.
On your replacements did you purchase from the original supplier?
How did the replacement prices and shipping costs compare per cell to the original 16?
Did you try at all to suggest the cell was defective and ask for compensation-if so how did they respond?
How was your experience overall with the supplier?
Ya, lots of questions.....but I am about to do what you did.......but hopefully.........without the bloating part.....
I appreciate your share so we can all learn.
Frank in Thailand
making mistakes so you don't have to...
Sadly I've bloated / pillowed my cell in the first few days, doing a capacity test and charging it afterwards.
My charger was possible set to CC (constant current)
Anyways, I was "lucky" to be able a new 152Ah cell with my next order.
Since then, several months have passed and I have been using the pillowed cell for tons of other things.
Always nice to have a 3.2v battery
In those months, more of my 152Ah cells got little or more bloating.
And some of the 280's start also.
I've done a TON of research on this topic.
It is perfectly normal behaviour!!!
The cells are not damaged.
Yes, it looks funny / strange / concerning.
Capacity wise, life cycle still the same.
Lithium-ion are notorious for this.
The problem with them is not so much with safety or capacity, it's the shape.
Mobile phone screen get cracked, or the battery cover no longer fits.
In RC, the pouch no longer fits in the plane / car / drone / whatever..
Capacity wise... Not a problem!!
Puncture it, that is a problem and where the fear originates!
With lithium ion, those gasses are flammable. That is what makes lithium ion dangerous goods to transport, and even responsible for plane crashes.
In event of a short, the cell heats up, makes loads of gasses, breaks and the rest is a small spark that egnite the explosive flammable gass.
Lucky we have Lifepo4!!
Not lithium ion!
I can not advise to inhale the gass escaping from the vent, that probably is nasty. But it's NOT flammable!!
On this forum there are several YouTube videos showing lifepo4 abuse. Shot at, punctured, shorted (100ah can give 1300A), burned for half an hour, etc etc etc.
No explosion, no fire, no flames.
Boring actually!!
Even a full short of a fully charged 100Ah was almost boring to watch.
Naturally, it bloated, the vent bursted, you see gass escaping. That was it..
No spectacular things like with lithium Ion. Boring...
And... After this full short and vented cap, the cell still works. I can't say anything about the rest of the life cycle, but it did work!! Amazing!
Some background information on the gassing, this part is the same for lithium ion and lifepo4.
During the initial charge there is a special section in the pouches to collect the gasses that's formed, and sealed + cut after this first charge.
True, not all lifepo4 have pouches inside, some have layers that aren't sealed in a pouch, only in the cell
(What is fine also!)
How they technically do this at those cells, I don't know. Most likely they place the vent after initial charge.
Many people compress their cells, even @Will Prowse shows this in his videos.
That isn't only just to keep the cells nice together, it's also to prevent bloating!!
Newer lithium-ion pouches for RC have a tiny bit reinforcement, enough to prevent the bloating.
CALB cells have strong plastic housing, to prevent this from happening.
Our Eve cells??
Almost nothing!
Thin, flexible aluminium.
Even the slightest bit of gass will make it bloated.
This doesn't mean that there is no bloating force in the CALB cells, there still is.
The housing is built to withstand this force. That's all.
We are all (myself included) using cells with paper thin walls without any protection against bloating, and complain when it does...
That's actually kinda stupid.
The cells aren't wrong or bad, we are.
We are abusing the cells outside specifications.
These cells are intended to be compressed mounted, not stand alone.
It's our lack of knowledge how to properly use the cells that makes them look funny.
Not broken, not defective, not dangerous.
This is NOT lithium ion!!!
I have used my cell a lot the last 3 months.
I even had it back in my battery array for a few weeks, replace a "healthy" cell.
My array is 3* 152 and one 280Ah per parallel set, 16 in series.
736Ah or roughly 37.5 kWh
No difference at all! (In terms of usage)
I have less bloated cells then the one I pillowed, it makes my array look funny.
That's all.
It looks different. Correct.
Can you still use? Yes you can!!
Can you still use it like the "healthy" (not bloated) cells? Yes you can!!
And you should.
besides having some gass inside there is absolutely no change in the internal chemistry or capacity or whatsoever.
The fear originates from lithium ion battery. Not lifepo4.
If you have a hard time believing this, please do a search on YouTube for lithium-ion and lifepo4 battery abuse.
You'll find the lifepo4 boring compared to the sparks and explosions that happened with lithium Ion.
De-bloating..
That's an interesting test.
I don't think I can safely de-bloat my pillowed cell.
The other cells that have some mild bloating like yours, I think it is possible.
I am going to try.
The steps are simple:
Compact!
Use 2 metal or wooded sheets (or other strong material) and compress the cells together.
I'm using aluminium strips and threaded rods to do this, for all my cells.
4 in a parallel set, 16 series.
I will put some syrofoam between the cells.
And compact.
Don't overdo it!!!
Gass can turn back to liquid in higher pressure.
The gassing is normal.
Being not compressed is not (or have strong walls that can handle the internal pressure without bloating)
A full battery is supposed to have more gass then discharged one.
Also, most gassing occur during charge or fast discharge.
Logically, at lower SOC the pressure should be less.
Perfect time to tighten the sheets a little more.
After several cycles it should be possible to tighten a little more, using the same force as used the first time.
The tension / pressure reduces as the gass is slowly getting back to liquid.
That is in theory.
I am going to do this, once my bus-bar project, melting copper and pouring in casting, is finished.
(Sadly, that goes a lot slower than hoped!)
I was "stupid" to ignore the advice given by @Will Prowse , to compact the cells.
I'm fairly confident that "re-pressuring" the cells will give them more their original shape back, but most of all, prevent the cells that are not yet bloating, to do so.
Seeing the videos of lifepo4 abuse and the time it takes before the vent burst, it can handle quite some pressure.
Just normal behaviour for Lifepo4 cells that aren't compressed placed (as they should be) to start bloating.
Nothing to worry about.
Safe to use.
Same lifecycle.
Just look funny.
It is NOT Lithium ion !!
My charger was possible set to CC (constant current)
Anyways, I was "lucky" to be able a new 152Ah cell with my next order.
Since then, several months have passed and I have been using the pillowed cell for tons of other things.
Always nice to have a 3.2v battery
In those months, more of my 152Ah cells got little or more bloating.
And some of the 280's start also.
I've done a TON of research on this topic.
It is perfectly normal behaviour!!!
The cells are not damaged.
Yes, it looks funny / strange / concerning.
Capacity wise, life cycle still the same.
Lithium-ion are notorious for this.
The problem with them is not so much with safety or capacity, it's the shape.
Mobile phone screen get cracked, or the battery cover no longer fits.
In RC, the pouch no longer fits in the plane / car / drone / whatever..
Capacity wise... Not a problem!!
Puncture it, that is a problem and where the fear originates!
With lithium ion, those gasses are flammable. That is what makes lithium ion dangerous goods to transport, and even responsible for plane crashes.
In event of a short, the cell heats up, makes loads of gasses, breaks and the rest is a small spark that egnite the explosive flammable gass.
Lucky we have Lifepo4!!
Not lithium ion!
I can not advise to inhale the gass escaping from the vent, that probably is nasty. But it's NOT flammable!!
On this forum there are several YouTube videos showing lifepo4 abuse. Shot at, punctured, shorted (100ah can give 1300A), burned for half an hour, etc etc etc.
No explosion, no fire, no flames.
Boring actually!!
Even a full short of a fully charged 100Ah was almost boring to watch.
Naturally, it bloated, the vent bursted, you see gass escaping. That was it..
No spectacular things like with lithium Ion. Boring...
And... After this full short and vented cap, the cell still works. I can't say anything about the rest of the life cycle, but it did work!! Amazing!
Some background information on the gassing, this part is the same for lithium ion and lifepo4.
During the initial charge there is a special section in the pouches to collect the gasses that's formed, and sealed + cut after this first charge.
True, not all lifepo4 have pouches inside, some have layers that aren't sealed in a pouch, only in the cell
(What is fine also!)
How they technically do this at those cells, I don't know. Most likely they place the vent after initial charge.
Many people compress their cells, even @Will Prowse shows this in his videos.
That isn't only just to keep the cells nice together, it's also to prevent bloating!!
Newer lithium-ion pouches for RC have a tiny bit reinforcement, enough to prevent the bloating.
CALB cells have strong plastic housing, to prevent this from happening.
Our Eve cells??
Almost nothing!
Thin, flexible aluminium.
Even the slightest bit of gass will make it bloated.
This doesn't mean that there is no bloating force in the CALB cells, there still is.
The housing is built to withstand this force. That's all.
We are all (myself included) using cells with paper thin walls without any protection against bloating, and complain when it does...
That's actually kinda stupid.
The cells aren't wrong or bad, we are.
We are abusing the cells outside specifications.
These cells are intended to be compressed mounted, not stand alone.
It's our lack of knowledge how to properly use the cells that makes them look funny.
Not broken, not defective, not dangerous.
This is NOT lithium ion!!!
I have used my cell a lot the last 3 months.
I even had it back in my battery array for a few weeks, replace a "healthy" cell.
My array is 3* 152 and one 280Ah per parallel set, 16 in series.
736Ah or roughly 37.5 kWh
No difference at all! (In terms of usage)
I have less bloated cells then the one I pillowed, it makes my array look funny.
That's all.
It looks different. Correct.
Can you still use? Yes you can!!
Can you still use it like the "healthy" (not bloated) cells? Yes you can!!
And you should.
besides having some gass inside there is absolutely no change in the internal chemistry or capacity or whatsoever.
The fear originates from lithium ion battery. Not lifepo4.
If you have a hard time believing this, please do a search on YouTube for lithium-ion and lifepo4 battery abuse.
You'll find the lifepo4 boring compared to the sparks and explosions that happened with lithium Ion.
De-bloating..
That's an interesting test.
I don't think I can safely de-bloat my pillowed cell.
The other cells that have some mild bloating like yours, I think it is possible.
I am going to try.
The steps are simple:
Compact!
Use 2 metal or wooded sheets (or other strong material) and compress the cells together.
I'm using aluminium strips and threaded rods to do this, for all my cells.
4 in a parallel set, 16 series.
I will put some syrofoam between the cells.
And compact.
Don't overdo it!!!
Gass can turn back to liquid in higher pressure.
The gassing is normal.
Being not compressed is not (or have strong walls that can handle the internal pressure without bloating)
A full battery is supposed to have more gass then discharged one.
Also, most gassing occur during charge or fast discharge.
Logically, at lower SOC the pressure should be less.
Perfect time to tighten the sheets a little more.
After several cycles it should be possible to tighten a little more, using the same force as used the first time.
The tension / pressure reduces as the gass is slowly getting back to liquid.
That is in theory.
I am going to do this, once my bus-bar project, melting copper and pouring in casting, is finished.
(Sadly, that goes a lot slower than hoped!)
I was "stupid" to ignore the advice given by @Will Prowse , to compact the cells.
I'm fairly confident that "re-pressuring" the cells will give them more their original shape back, but most of all, prevent the cells that are not yet bloating, to do so.
Seeing the videos of lifepo4 abuse and the time it takes before the vent burst, it can handle quite some pressure.
Just normal behaviour for Lifepo4 cells that aren't compressed placed (as they should be) to start bloating.
Nothing to worry about.
Safe to use.
Same lifecycle.
Just look funny.
It is NOT Lithium ion !!
A little expansion (1mm) is fine. What the OP posted is not. I suggest you check you charge voltages and bms. You are over volting, something is absolutely wrong.
LFP IS lithium ion... Lithium salts are dissolved in an organic electrolyte. By definition it is flammable. The level varies with the cell maker. LFP has a lower energy density and thermal coefficient. So when it goes into thermal runaway, its much less likely to reach the ignition temperature and catch fire compared to other lithium based chemistries (cathode materials with cobalt for example). In this case the cathode is FePO4.
ANY venting of a cell indicates electrolyte breakdown. This means electrolyte byproducts, voids in the cell sandwich, and other issues. AVOID.
LFP IS lithium ion... Lithium salts are dissolved in an organic electrolyte. By definition it is flammable. The level varies with the cell maker. LFP has a lower energy density and thermal coefficient. So when it goes into thermal runaway, its much less likely to reach the ignition temperature and catch fire compared to other lithium based chemistries (cathode materials with cobalt for example). In this case the cathode is FePO4.
ANY venting of a cell indicates electrolyte breakdown. This means electrolyte byproducts, voids in the cell sandwich, and other issues. AVOID.
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