Author Topic: Don't keep fully charged Li-Ion in long term storage, they tend to bulge  (Read 7503 times)

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Online SiliconWizard

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #50 on: January 17, 2023, 08:37:26 pm »
Very low charge rates should be avoided , ie below 0.2 C as  very low  charging rates encourages SEI layer growth and hence leads to battery degradation.  Chargers at 0.5c then stop charging once full no float etc needed. Track SOC band restart charging at a point

In my experience mentioned earlier, a combination of a 0.1C charge current and automatically recharging the battery, keeping it at 100% most of the time, was a sure recipe for dangerous bulging and killing the batteries.

Thus, any UPS system based on Li-ion batteries should definitely be designed appropriately, and there's little surprise lead-acid batteries are still popular in UPSs.
 

Online thm_w

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #51 on: January 17, 2023, 11:05:57 pm »
Very low charge rates should be avoided , ie below 0.2 C as  very low  charging rates encourages SEI layer growth and hence leads to battery degradation.  Chargers at 0.5c then stop charging once full no float etc needed. Track SOC band restart charging at a point

Long term storage is best at 60-70 % SOC but really fine upto 80% SOC avoid very low Soc for storage or below 40% SOC

In essence short high current charge ( relatively high ) is best once the correct safety regime and a proper stop charge point is set

Citation? What I'm reading shows the opposite.
And any any sort of cycle life studies all get better as charge rate decreases, down to 0.2C or 0.1C, is about the lowest. I don't see any studies lower than that.

"Temperature rise due to reaction and joule heating accelerates the SEI layer growth and causes more capacity loss" https://iopscience.iop.org/article/10.1149/06127.0043ecst

This might be relevant to what you are talking about though: "The kinetically limited expressions from equations 2 and 3 are qualitatively similar, with both showing much greater SEI growth during the later stages of charging, especially the CV portion of charging. "
https://iopscience.iop.org/article/10.1149/2.1161412jes
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Offline MadScientist

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #52 on: January 17, 2023, 11:11:05 pm »
The studies are there if you Google them. Trickle charging has never been recommended for li ie very low fractions of C

Li performs best if the charge cycle is as short as practical consistent with safety and battery max specs
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Online tom66

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #53 on: January 17, 2023, 11:19:10 pm »
0.1-0.2C charging rate would be about normal for an EV battery (~60kWh pack, 7kW AC charger), yet the data shows that rapid charging (while the effect is not hugely significant) is definitely more damaging to the cells than slow charging.  So I'm not sure I accept the SEI layer buildup stuff.
 
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Online thm_w

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #54 on: January 17, 2023, 11:36:49 pm »
The studies are there if you Google them. Trickle charging has never been recommended for li ie very low fractions of C

Li performs best if the charge cycle is as short as practical consistent with safety and battery max specs

rightttt so its on me to find the proof of your claim, which contests with existing studies.
Lower charge rates results in longer cycle life, down to 0.2C or lower.

https://www.researchgate.net/figure/Capacity-development-vs-equivalent-full-cycles-depending-on-the-charging-rate-of_fig4_286242928
https://www.sciencedirect.com/science/article/abs/pii/S0378775318310462
https://pubs.rsc.org/en/content/articlelanding/2018/ra/c8ra04074e (LiFePO4)
https://www.osti.gov/servlets/purl/1397110 (some C/10 cycle tests)
« Last Edit: January 17, 2023, 11:38:39 pm by thm_w »
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Offline JDubU

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #55 on: January 18, 2023, 12:34:36 am »
RoGeorge:

Do not puncture a lithium ion battery pouch under any circumstances!!!  :palm:

The liquid electrolyte is a lithium fluoride compound that will convert to hydrofluoric acid in the presence of moisture.  Hydrofluoric acid is a very dangerous contact poison.

It also stops being a battery if any moisture is present in the electrolyte.
« Last Edit: January 18, 2023, 12:37:53 am by JDubU »
 
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Offline RoGeorgeTopic starter

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #56 on: January 18, 2023, 09:50:56 am »
Thanks for the warning.  Did that outdoors.  Poked a pinhole in the swollen layer only, let the gasses inside escape and squeeze/flatten the battery case, then covered the pinhole with self adhesive Scotch-like tape.  The pressure inside was bigger, so I hope not much air entered the battery.  Also it's winter here, so even if some air entered the battery, humidity was low.

I knew abut nasty HF and avoid inhaling, thought it smelled sweet for a short moment.  The sweet smell reminded a little about vintage electronics and tube radios, that smell very close to the sweet smell of very old paper books with yellowish pages.  Not the same smell, but close.

The battery is a small 300mAh Li-Ion that was so bulged (about 3-4 times its nominal thickness) that I had to remove it from a TEAC mp3 player years ago.  It sat bulged like that and unused on a shelf for about 10 years.  Charged discharged it before and after deflating.  Still working, just that it lost about 1/3 of its capacity over the years.  For now I don't plan to reuse that battery.

As for the other Li-Ion batteries leftovers from mobile phones, if I will ever reuse them, will let them bulged as they are.  No need to deflate since the DIY enclosures can be made big enough.

Offline tooki

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #57 on: January 18, 2023, 07:05:39 pm »
As for the other Li-Ion batteries leftovers from mobile phones, if I will ever reuse them, will let them bulged as they are.  No need to deflate since the DIY enclosures can be made big enough.
Are you insane?!?

A swollen lipo pouch belongs in exactly one place: the recycling bin. Continuing to use it is asking for trouble.

And when I say trouble, here’s some context: every Apple Store has a battery fire box and basic firefighting equipment in their repair room — and this despite the fact that if a device comes in with a swollen battery, they won’t touch the battery in-store, and instead replace the device and then refurbish the swollen device in a repair depot. (Battery swaps are done in-store if the battery isn’t swollen.)
 

Offline Siwastaja

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #58 on: January 18, 2023, 08:18:11 pm »
0.1-0.2C charging rate would be about normal for an EV battery (~60kWh pack, 7kW AC charger)

Or even just 2-2.5kW, so 0.05C is perfectly normal.

Never heard about the low current SEI thing, either. Have read quite a few papers.
 
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Offline james_s

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #59 on: January 18, 2023, 09:02:23 pm »
Very low charge rates should be avoided , ie below 0.2 C as  very low  charging rates encourages SEI layer growth and hence leads to battery degradation.  Chargers at 0.5c then stop charging once full no float etc needed. Track SOC band restart charging at a point

In my experience mentioned earlier, a combination of a 0.1C charge current and automatically recharging the battery, keeping it at 100% most of the time, was a sure recipe for dangerous bulging and killing the batteries.

Thus, any UPS system based on Li-ion batteries should definitely be designed appropriately, and there's little surprise lead-acid batteries are still popular in UPSs.

Regular Li-ion is a poor choice for UPS duty. LiFePO4 is a much better choice, they are way more robust and tolerate fully charged storage well. They're a lot harder to make catch fire too.The energy density is lower which limits their use in portable electronics and flying toys but they do get used in power tools.
 

Offline Bud

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #60 on: January 18, 2023, 09:09:25 pm »
.. if a device comes in with a swollen battery, they won’t touch the battery in-store, and instead replace the device and then refurbish the swollen device in a repair depot.
That is just "think of the children" mentality.
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Offline james_s

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #61 on: January 18, 2023, 09:14:44 pm »
.. if a device comes in with a swollen battery, they won’t touch the battery in-store, and instead replace the device and then refurbish the swollen device in a repair depot.
That is just "think of the children" mentality.

It is a bit silly. Just drain the battery, a battery in a low state of charge, whether swollen or not is pretty inert.
 

Online SiliconWizard

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #62 on: January 18, 2023, 09:17:00 pm »
As for the other Li-Ion batteries leftovers from mobile phones, if I will ever reuse them, will let them bulged as they are.  No need to deflate since the DIY enclosures can be made big enough.
Are you insane?!?

He got warned enough, I think. Now he mentioned a pretty low-capacity battery, so the risk was minimal in terms of fire. The nasty chemicals, OTOH, is something else.

A swollen lipo pouch belongs in exactly one place: the recycling bin. Continuing to use it is asking for trouble.

Yes, but not in the general trash bin, please. This is dangerous and illegal in most places. Dispose of it in appropriate bins.
« Last Edit: January 18, 2023, 09:20:21 pm by SiliconWizard »
 

Online SiliconWizard

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #63 on: January 18, 2023, 09:19:20 pm »
Very low charge rates should be avoided , ie below 0.2 C as  very low  charging rates encourages SEI layer growth and hence leads to battery degradation.  Chargers at 0.5c then stop charging once full no float etc needed. Track SOC band restart charging at a point

In my experience mentioned earlier, a combination of a 0.1C charge current and automatically recharging the battery, keeping it at 100% most of the time, was a sure recipe for dangerous bulging and killing the batteries.

Thus, any UPS system based on Li-ion batteries should definitely be designed appropriately, and there's little surprise lead-acid batteries are still popular in UPSs.

Regular Li-ion is a poor choice for UPS duty. LiFePO4 is a much better choice, they are way more robust and tolerate fully charged storage well. They're a lot harder to make catch fire too.The energy density is lower which limits their use in portable electronics and flying toys but they do get used in power tools.

Definitely. I would never use Li-ion for back-up power purposes, even for relatively low capacities, after this unfortunate design.
But we can still see back-up systems with Li-ion batteries, and see people asking about that on forums on a regular basis, so I think it's worth talking about it.

And LiFePO4 is much, much better indeed. That's what I would recommend as well.
 

Offline james_s

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #64 on: January 18, 2023, 09:22:23 pm »
As for the other Li-Ion batteries leftovers from mobile phones, if I will ever reuse them, will let them bulged as they are.  No need to deflate since the DIY enclosures can be made big enough.
Are you insane?!?

He got warned enough, I think. Now he mentioned a pretty low-capacity battery, so the risk was minimal in terms of fire. The nasty chemicals, OTOH, is something else.

A swollen lipo pouch belongs in exactly one place: the recycling bin. Continuing to use it is asking for trouble.

Yes, but not in the general trash bin, please. This is dangerous and illegal in most places. Dispose of it in appropriate bins.

It's always been accepted practice in the USA to discharge pouch cells and throw them in the regular trash, I'm not aware of any regulations against doing that.

Those little ones that are under about 500mAh are pretty safe. I have burned up a worn out one on purpose before to see what would happen. It wasn't very exciting, it just puffed way up, melted a hole and then there was a flame much like from a candle that came out for a few seconds and then it sat there smoking.
 

Offline RoGeorgeTopic starter

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #65 on: January 18, 2023, 09:28:23 pm »
How did you ignite it?

Online SiliconWizard

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #66 on: January 18, 2023, 09:35:38 pm »
As for the other Li-Ion batteries leftovers from mobile phones, if I will ever reuse them, will let them bulged as they are.  No need to deflate since the DIY enclosures can be made big enough.
Are you insane?!?

He got warned enough, I think. Now he mentioned a pretty low-capacity battery, so the risk was minimal in terms of fire. The nasty chemicals, OTOH, is something else.

A swollen lipo pouch belongs in exactly one place: the recycling bin. Continuing to use it is asking for trouble.

Yes, but not in the general trash bin, please. This is dangerous and illegal in most places. Dispose of it in appropriate bins.

It's always been accepted practice in the USA to discharge pouch cells and throw them in the regular trash, I'm not aware of any regulations against doing that.

Certainly not in the EU, at least! There is always this crossed waste bin symbol to make it clear.

https://www.compliancegate.com/lithium-battery-safety-standards-european-union/
 

Offline james_s

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #67 on: January 18, 2023, 10:37:01 pm »
How did you ignite it?

Connected to a bench PSU and overcharge it, they self ignite.
 
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Offline RoGeorgeTopic starter

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #68 on: January 19, 2023, 12:26:36 am »
What current voltage did it caught fire?
Was that with or without the small Battery Management System PCB on top of the battery?

The mobile phone cells always come with a small BMS inside.  I know for sure the BMS will disconnect the battery at lower than 2.8V (it happened with a few batteries while I was discharging them to measure their capacity).

The internal BMS is also supposed to disconnect the cell at more than 4.3V charging, or at a short circuit (high current, don't know which I value).  So far never tested the overvoltage and the overcurrent limits.

Offline amyk

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #69 on: January 19, 2023, 01:52:56 am »
RoGeorge:

Do not puncture a lithium ion battery pouch under any circumstances!!!  :palm:

The liquid electrolyte is a lithium fluoride compound that will convert to hydrofluoric acid in the presence of moisture.  Hydrofluoric acid is a very dangerous contact poison.

It also stops being a battery if any moisture is present in the electrolyte.
You'll get HF if the battery burns (due to fluoropolymers being used in the separator), but the electrolyte itself is relatively tame.
 

Offline james_s

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #70 on: January 19, 2023, 02:04:53 am »
What current voltage did it caught fire?
Was that with or without the small Battery Management System PCB on top of the battery?

The mobile phone cells always come with a small BMS inside.  I know for sure the BMS will disconnect the battery at lower than 2.8V (it happened with a few batteries while I was discharging them to measure their capacity).

The internal BMS is also supposed to disconnect the cell at more than 4.3V charging, or at a short circuit (high current, don't know which I value).  So far never tested the overvoltage and the overcurrent limits.

I don't recall the voltage, it was a few years ago and there was obviously some drop over the wires anyway. It was a model aircraft battery without any BMS, I've heard other cases of them catching fire around 5-6V. There have been quite a few fires, mostly from people setting up their chargers incorrectly, some of the older chargers didn't monitor the balance leads. Multiple guys on the RC forum lost their houses, several others had workshops and cars burn down.
 
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Offline JDubU

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #71 on: January 19, 2023, 06:53:50 am »
You'll get HF if the battery burns (due to fluoropolymers being used in the separator), but the electrolyte itself is relatively tame.

Take a look at this:
https://www.nature.com/articles/s41598-017-09784-z
 

Offline tooki

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #72 on: January 19, 2023, 07:42:00 am »
.. if a device comes in with a swollen battery, they won’t touch the battery in-store, and instead replace the device and then refurbish the swollen device in a repair depot.
That is just "think of the children" mentality.
No, it’s simple risk mitigation (which insurance companies likely insist on) and time management. It’s not worth the time of store employees to figure out if a battery is discharged enough to be worked on safely. (A battery replacement is a 15 minute schedule slot.) Just send the customer home happy, quickly, and let the repair depot deal with it later.

The point is, batteries in that state are certainly not safe enough to be put back into service!!


A swollen lipo pouch belongs in exactly one place: the recycling bin. Continuing to use it is asking for trouble.

Yes, but not in the general trash bin, please. This is dangerous and illegal in most places. Dispose of it in appropriate bins.
Yep, which is why I said recycling, not trash. (I assume enough intelligence on the part of our readers to understand that this means the correct bin for the item being disposed of. …ok, fair enough, given that this dude wants to reuse it, it probably does need to be stated explicitly!) Put used batteries into the battery recycling bin.
 

Online magic

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #73 on: January 19, 2023, 09:19:32 am »
The point is, batteries in that state are certainly not safe enough to be put back into service!!
They certainly don't look good, and I imagine that alone would be an overriding concern at Fruit Inc™ >:D


This whole thread rises more questions than it answers. Maybe some experimentation would be in order.

Are discharged batteries really inert and inflammable? What if you outright put one in fire?
Is there enough HF in a swollen battery to actually poison yourself?
How many normal charge cycles before a swollen battery catches on fire? Does it ever?

 :popcorn:

BTW, I have seen a swollen battery which apparently had been in use for a while, without the owner noticing.
The owner only complained about capacity not being what it used to be.
 

Offline RoGeorgeTopic starter

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Re: Don't keep fully charged Li-Ion in long term storage, they tend to bulge
« Reply #74 on: January 19, 2023, 09:37:03 am »
(I assume enough intelligence on the part of our readers to understand that this means the correct bin for the item being disposed of. …ok, fair enough, given that this dude wants to reuse it, it probably does need to be stated explicitly!) Put used batteries into the battery recycling bin.

Would you kindly fuck off?
Hold your innuendos for yourself.

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