Lipo Battery blown up/inflated problem.

[touchh]

I've been following Dave's USB Power Supply and doing a similar project myself, I really liked the Turnigy batteries he was using from HobbyKing so I ordered some for myself. I picked the 1s 2200mah version, I think I paid four bucks each, great price I thought! I did some testing with them, mainly charging/discharging (with the proper protection circuitry!) and they seemed to be close to the rated capacity.

Then I set them aside for about a month til I had time to get back on the project. Yesterday I went out to my workshop and found that out of the three I had ordered, two were "inflated" to about 2x their size and reading 0.0 volts, when I left them after my initial testing I used my IMAX B6 to charge them to %40 as recommended by most lipo battery manufacturers and kapton taped the terminals and at the hottest times of the day my workshop barely goes over 85F, so I'm 98% sure that this is no fault of my own. Any idea what caused this? Hobbyking says its a defective battery or misuse, but say's they'll replace them (but they have yet to respond to my support ticket).

I'm really a bit weary now of using lipo batteries, I've used Samsung 18650's before in similar projects and never had a problem but even now I'm thinking of switching to LiFePO batteries.

So now I'm scratching my head trying to figure out what exactly happened!

[westfw]

mainly charging/discharging (with the proper protection circuitry!)

"protection circuitry" is generally a different thing than "proper charging circuitry."  Did you have both?
(I guess the b6 charger should have done things correctly, as long as it was configured correctly.)

That said, it has been my observation with cheap "consumer-packaged" batteries (for cameras or cellphones) that it is not so much that they start out with poor capacity, but that they deteriorate much more rapidly than brand-name cells.

[John Coloccia]

Did you monitor temperature during the charge/discharge cycles?  Incidentally, if you're playing around with these things and smell something like candy or bubble gum, get the fire extinguisher ready   Actually, it's not a bad idea to give new packs a sniff....especially cheap packs.  A strong, sweet smell can be bad news, and I have occasionally gotten new packs that are damaged.

[touchh]

Did you monitor temperature during the charge/discharge cycles?  Incidentally, if you're playing around with these things and smell something like candy or bubble gum, get the fire extinguisher ready   Actually, it's not a bad idea to give new packs a sniff....especially cheap packs.  A strong, sweet smell can be bad news, and I have occasionally gotten new packs that are damaged.

Yes, the imax b6 has a temp sensor. I cant recall the temp though, and as I was not fast charging them they never got over warm to the touch.

Interesting about the candy smell! never knew about that.

[touchh]

mainly charging/discharging (with the proper protection circuitry!)

"protection circuitry" is generally a different thing than "proper charging circuitry."  Did you have both?
(I guess the b6 charger should have done things correctly, as long as it was configured correctly.)

Good point, the protection was only for discharge/overcurrent. I rely on the imax b6 to properly charge them and it's never failed me yet (I've used it with a bunch of 18650's)

[digsys]

We use a lot of these type of cell "pouches" and have had MANY end up like that, over the years. Often, it is due to manufacturing
faults, sometimes excessive or certain resonant vibration, sometimes heat etc In fact I have 4x7 cell packs to autopsy tomorrow,
these I'm pretty sure are resonant vibration issues. If you do a teardown, you'll find several layers of wrapped electrodes, with
very little force holding them together. They can de-laminate quite easily if not made perfectly. In a "long life" pack, you're supposed
to provide a "clamping" force, and still retain air-flow. IF you were that careful, then I'd go for manufacture error.

[John Coloccia]

I've never taken one of these things apart.

Well, not on purpose, anyway...

Is there a safe way to teardown one of these batteries outside of a lab setting?

[digsys]

   Is there a safe way to teardown one of these batteries outside of a lab setting? 

The chemicals are only really dangerous when superheated / vapour stage. IF there was any real danger with LiPos, we'd
have several dead members by now :-) (as we've been pulling these apart for 25+ yrs)
Plus there's always several around the workshop, either leaking or that have dropped their goo :-)
You do get to "know" the smell quite easily and quickly, which is a good thing. As for doing autopsies, maybe just like CSI on TV?
Wear rubber gloves, if you want. I don't bother, just wash my hands well afterwards.

Edit: We've found MANY manufacturer defects this way over the years.

[touchh]

digsys thanks for all the valuable info! I'll definitely do a teardown and see what I find. I noticed that the two cells that failed both had marks on them almost as if they had been hit with tiny pellets of some sort.. So maybe that helped them in failing.

I noticed you mentioned clamping, is that why most prebuilt 2+ cell batteries have a very rigid plastic heat-shrink around them but not on the ends?

It's reassuring to know that they don't just blow up like fire and brimstone unless you abuse them. I've been messing with li-ion and li-po batteries lately because I've got so tired of nimh/SLA batterys just performing piss poorly in about everything.

This is my first time experimenting with li-po, I've done quite a bit with li-ion. I use a bunch of cordless power tools that are maybe 8 years old but I really enjoy the quality, as they were made in America and have performed without problem for years, but the batteries SUCK and are expensive, so I tore the old batteries down and made new ones with 18650 cells (Samsung makes great 2600mah cells) and I was so amazed at the fact that with the old batteries sometimes I would use up 2-3 batteries a day where as now one battery lasts me almost an entire day. I've also found a great source of li-ion cells to be used/broke laptop batteries, most of the time there is either nothing wrong or just one or two dead cells.

[digsys]

I noticed that the two cells that failed both had marks on them almost as if they had been hit with tiny pellets of some sort.. So maybe that helped them in failing.

Yes, during an autopsy be VERY aware of tiny particles that don't belong there, tiny tears, colourations and ESPECIALLY check the tabs !!
You'll see multiple wraps all micro-spotted or crimped to a tin or other tab material. This varies for each manufacturer. Many of the failures
start here. Also, we often find leaks in the pouch sealing. IF you can smell anything at all, there's a pinprick or de-lamination..

I noticed you mentioned clamping, is that why most prebuilt 2+ cell batteries have a very rigid plastic heat-shrink around them but not on the ends?

IF a pack is well made and used in spec, it does NOT need to be compressed. They do it for retail because they have no idea what monkeys
will do with the cells. We've done a lot of experimentation and decided to NEVER compress ours. IF a pouch EVERY gets to the point where it's
built up enough pressure that it can "bulge", it's already TOO late, some damage has been done - usually to the internal chemistry.
You can think of a cell as being exactly like a capacitor, with the layer spacing being quite critical. There really no "force" applied at the ends,
plus you need venting and thermal cooling ability from somewhere.

[amyk]

My guess is high self-discharge from a partial internal short that caused it to die.

The smell is probably dimethoxyethane.

[Fraser]

Interestingly my fathers new Canon compact camera instructions makes comment that the LiPo battery may bulge during use and only needs to be replaced if the bulging hinders installation or removal. They stated that some bulging is 'normal' After reading this thread I would contest that view in a consumer product.  I haver seen bulging camera battery packs but that was always accompanied by battery failure.

[Psi]

How did you charge them to 40% ?
You're supposed to select the "Storage charge" mode and let the charger do it for you.

[nixxon]

Did you monitor temperature during the charge/discharge cycles?  Incidentally, if you're playing around with these things and smell something like candy or bubble gum, get the fire extinguisher ready   Actually, it's not a bad idea to give new packs a sniff....especially cheap packs.  A strong, sweet smell can be bad news, and I have occasionally gotten new packs that are damaged.

Yes, the imax b6 has a temp sensor. I cant recall the temp though, and as I was not fast charging them they never got over warm to the touch.

Interesting about the candy smell! never knew about that.

Temp sensor:I believe the temp sensor is intended used when charging NiCd or Ni-MH cells (my charger actually came with a temp sensor with a curved surface with a magnet to snap on to cylindrical (AA-style) metal batteriy cases).

Overloaded during discharge?:
LiPos are usually designed for 10C or more discharge rate and the charger's low discharge load (max 1A) is applying very little stress to the battery.

Monitoring:
You should always check the voltage on each individual LiPo cell during and after each charge or discharge and veryfy that the charger never applies more than 4.20 Volts/cell or less than approx. 3.2 Volts/cell.

[nukie]

The temp sensor is there to reduce risk of fire, lithium has high charging efficiency so if it heats up there's something wrong. Attach the sensor for safety.

[touchh]

How did you charge them to 40% ?
You're supposed to select the "Storage charge" mode and let the charger do it for you.

I believe I read that "storage charge" levels them off to 40%, but I may be wrong.

Did you monitor temperature during the charge/discharge cycles?  Incidentally, if you're playing around with these things and smell something like candy or bubble gum, get the fire extinguisher ready   Actually, it's not a bad idea to give new packs a sniff....especially cheap packs.  A strong, sweet smell can be bad news, and I have occasionally gotten new packs that are damaged.

Yes, the imax b6 has a temp sensor. I cant recall the temp though, and as I was not fast charging them they never got over warm to the touch.

Interesting about the candy smell! never knew about that.

Temp sensor:I believe the temp sensor is intended used when charging NiCd or Ni-MH cells (my charger actually came with a temp sensor with a curved surface with a magnet to snap on to cylindrical (AA-style) metal batteriy cases).

Overloaded during discharge?:
LiPos are usually designed for 10C or more discharge rate and the charger's low discharge load (max 1A) is applying very little stress to the battery.

Monitoring:
You should always check the voltage on each individual LiPo cell during and after each charge or discharge and veryfy that the charger never applies more than 4.20 Volts/cell or less than approx. 3.2 Volts/cell.

My temp sensor is just a wire with headshrink around the sensor, so I tape it to the battery pack with kapton tape.

[Psi]

How did you charge them to 40% ?
You're supposed to select the "Storage charge" mode and let the charger do it for you.

I believe I read that "storage charge" levels them off to 40%, but I may be wrong.

Yep, somewhere around 30-40%.
I was just confused why you would call it that when everyone calls it "storage charge".
no prob, It just sounded like you were doing something unusual.

oh, something else to keep i mind.
Don't leave the batteries plugged into the charger when it's switched off.
It will flatten and destroy them.

[Tuomas]

I have a couple of similar lipo cells at home. I was originally planning on using them for a different project, but when I got my HF ham radio and wanted to use it portable, I needed a portable battery and I hackedthis thing together. I have also added a connector so I can monitor individual cell voltages and balance it. ~3300mAh 20C discharge rate, three in series.

 I just charge the pack with my bench supply, set to current limited 1A, voltage to 12v (so each individual cell is 4V). I check individual cell voltages before and after charging and balance manually if needed.

I've never noticed them rising above room temperature. I charge them at 1A, discharge is 800mA normally and up to 20A when transmitting with the radio. They haven't bulged at all. Seem to be working fine.

[touchh]

Did you get yours from hobbyking or somewhere else? I'm definitely going to give turnigy batteries another try, I'm just not sure if I'll be buying them from hobbyking or not, depends if they stand behind their product or give me a runaround.

Hobbyking replied today with this:

Thanks for contacting the HobbyKing Support Team.
There looks to be solder on the battery terminals can you please tell me why that is the case?

We'll see what they do about it I guess.

[amyk]

Don't leave the batteries plugged into the charger when it's switched off.
It will flatten and destroy them.

Thanks, now I have a mental image of batteries being crushed by a collapsing charger...

I have a couple of similar lipo cells at home. I was originally planning on using them for a different project, but when I got my HF ham radio and wanted to use it portable, I needed a portable battery and I hackedthis thing together. I have also added a connector so I can monitor individual cell voltages and balance it. ~3300mAh 20C discharge rate, three in series.

You should be careful not to crease or bend the cells, I'd put it in a hard case if I were you.

[peter.mitchell]

Did you get yours from hobbyking or somewhere else? I'm definitely going to give turnigy batteries another try, I'm just not sure if I'll be buying them from hobbyking or not, depends if they stand behind their product or give me a runaround.

Hobbyking replied today with this:

Thanks for contacting the HobbyKing Support Team.
There looks to be solder on the battery terminals can you please tell me why that is the case?

We'll see what they do about it I guess.

This is why they ask you that:

WARNING: Soldering Lipoly Cells takes a degree of skill and experience. Do not attempt to solder your own packs if you are not confident in your soldering abilities. No Warranty is implied or given once you have soldered the cell tabs. Please check cells for warranty purposes prior to soldering.

For hobbyking cells, i drill a hole and nut+screw+crimp connector, it keeps warranty in tact.

similar to this: http://i1035.photobucket.com/albums/a435/michaelpon12/2012-11-29033212.jpg

[touchh]

Did you get yours from hobbyking or somewhere else? I'm definitely going to give turnigy batteries another try, I'm just not sure if I'll be buying them from hobbyking or not, depends if they stand behind their product or give me a runaround.

Hobbyking replied today with this:

Thanks for contacting the HobbyKing Support Team.
There looks to be solder on the battery terminals can you please tell me why that is the case?

We'll see what they do about it I guess.

This is why they ask you that:

WARNING: Soldering Lipoly Cells takes a degree of skill and experience. Do not attempt to solder your own packs if you are not confident in your soldering abilities. No Warranty is implied or given once you have soldered the cell tabs. Please check cells for warranty purposes prior to soldering.

For hobbyking cells, i drill a hole and nut+screw+crimp connector, it keeps warranty in tact.

similar to this: http://i1035.photobucket.com/albums/a435/michaelpon12/2012-11-29033212.jpg

Ya, I'll certainly do something similar next time (or just use alligator clips in testing). That's an impressive battery pack you have there, looks like it has some serious capacity.

Ah, I did not see the warranty part when I bought them, I did however research the proper soldering of lipo tabs and followed it. I'm planning on making a video/pictures of a battery teardown and I'll post it here, maybe some of the more experienced member's can see something I missed.

[Tuomas]

Did you get yours from hobbyking or somewhere else? I'm definitely going to give turnigy batteries another try, I'm just not sure if I'll be buying them from hobbyking or not, depends if they stand behind their product or give me a runaround.

They are from hobby king, forgot to mention that. These things: http://www.hobbyking.com/hobbyking/store/__18593__Turnigy_3300mAh_1S_20C_Lipoly_Single_Cell_.html

You should be careful not to crease or bend the cells, I'd put it in a hard case if I were you.

Oh yes, they spend most of their time inside a padded ESD bag meant for shipping that just happens to be  the perfect size for the cells.

[westfw]

they spend most of their time inside a padded ESD bag

Hopefully not a "metal in" conductive ESD bag that might be conductive enough to over-discharge the cells!

[peter.mitchell]

That's an impressive battery pack you have there, looks like it has some serious capacity.

The picture isn't my picture, however, I have several packs very similar to it.

Lithium batteries are amazing.

[touchh]

Well, too bad... Hobbyking replied back today that they were not under warranty, that it was only a 30 day warranty, I contacted them 45 days after I purchased them, 15 days paste the warranty. It took them over 10 days to reply to my support tickets just to tell me they were going to squirm out of it.

I wouldn't recommend anyone shop at hobbyking IMO. I hate companies that don't stand behind their products. Anyone know any suppliers of lipo bare cells with decent customer support?