Bulging Li-Ion power packs

It's a well-known issue amongst electric model airplane pilots. We tend to demand more from our batteries, and we tend to use "naked" packs without any protection electronics.

So if you search around with "RC" in your search terms you'll find all sorts of tales of woe. RC pilots are taught to treat their LiPo packs like they'll burst into flame at any moment, especially while charging.

This video gives a good overview of the LiPo wisdom among RC guys:

With RC planes, the biggest culprit that causes puffing is overcharging, or charging them up to the limit and then letting them sit around fully charged for months. Puffed cells will work OK, but sometimes at reduced capacity.

As an incendiary device, a LiPo cell really sucks as far as dependability goes -- you can't reliably set them off without a hatchet, hammer & nail or other bit of sharp steel that'll violate the integrity of the outer envelope. But once started, they shoot hot flames for a good while, and would certainly catch stuff on fire.

For all that, one of my RC club members burnt his workshop down charging LiPo batteries. Another one burnt a hole through the scrap piece of carpet he was using trying to ferry a burning battery out to the back yard from his basement. Incidents of batteries catching fire at the field are rare, but have happened, particularly as a result of crashes or charging.

Much of the issues that RC guys face can be mitigated by charging the batteries conservatively and by matching the charging algorithm to the specific cell chemistry -- both of these are impractical for RC use. I suspect that your Apple batteries are just victims of old age, and possibly Apple landing a bit too far on the "fully charged vs. safe" spectrum when they designed their charging algorithm.

The recognized safe way to dispose of LiPo batteries is to chuck them in a bucket of saturated salt water for 24 hours -- the salt water discharges the battery at the same time that it provides a fire-proof blanket. After the battery is dead-dead then you can just chuck it in the trash.

The redneck way to safely dispose of LiPo batteries is to charge them fully, then tape them to a post and shoot at them with a varmint rifle. Good marksmanship is rewarded with flame. If you live someplace that dries out in summer this is best done during the rainy months, or after dousing the area around the post with water.

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Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com

putting any kind of batteries in the trash is a big no-no here, you just leave them net to the trash and they take them to recycling

-Lasse

Yep. That's common and "normal":

When a battery reaches some temperature, then a chemical in the Cobalt Oxide starts an exothermic (creates heat) reaction. More heat raises the cell temperature which causes more of the same chemical reaction, which liberates some gasses, and produces the battery of the bulge. Eventually, all this will end in either the battery pack catching fire or the reaction fizzles out leaving the battery in a swollen state.

One of my customers tossed such a battery into their office dumpster. About 12 hrs later, it caught fire. They put it out with a garden hose.

Not much. In order for the cell to get hot enough to ignite the lithium, it would need to be charging or possibly fully charged. There would also need to be something conductive to short the battery layers internally. In the various battery fire videos found on YouTube, that function is usually provided by pounding a nail through the battery pack or cell. Also, some LiIon chemistries ignite at a lower temperature than others (lithium cobalt oxide). See the Boeing Dreamliner battery fires for an example.

Maybe. 8 years ago was around the time of the 2006 and 2008 Sony battery recalls. Sony was shipping cells with metal shavings floating around inside. These perform the same function as pounding a nail through the battery and did cause a few unplanned meltdowns. However,

8 years is beyond what I would consider typical LiIon battery life, especially if it always left in the charger and running warm.

About 15 years ago, I was busted by the county for maintaining an unauthorized toxic waste dump of dead UPS batteries. Fortunately, I talked my way out of it. Yeah, I know the feeling.

To avoid an Apple bashing flame war, which always produces more heat than illumination, I'll refrain from disgorging my opinions on Apple design, construction, pricing, and service.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

My Razr cell phone battery started to bulge. The cover didnt fit properly. Never caught fire. I think it was 3 years old at the time. Never a problem like that with the replacements, so it wasn't charging circuit related.

Cheer

Well I'm glad I bothered now :)

This is all very interesting - thank you :)

:->

Old batteries start to have problems with excessive internal resistance and metal whiskers. The first symptom is bloating. The second symptom is that it bursts into flames.

Dead LiIon packs are still dangerous. LiIon cells are likely to explode if overcharged or over-discharged then recharged. As a result, all battery packs contain a circuit board that goes open-circuit when the battery voltage is outside a safe range. There's just enough power left in a "dead" pack to ignite the flammable electrolyte and gasses.

There are plenty of YouTube videos of people whacking "dead" battery packs with a rake and then having them shoot flames.

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I feel vindicated!

Old thread is still relevant! My 15-inch 2012 MacBook Pro has developed the bulge, too. (Apple's free battery replacement program only covers 13- inchers. Apple told me it's not covered; go to authorized service center.) I'd like to replace the cells. The replacement kit sells for about $50-90 USD. o Has anyone done the replacement? The job per iFixit is quite involved, nearly a full tear down. But YouTubers have posted shorter methods, removing fewer parts, and using fishing line to cut thru the glue (underneath the cells). o Once replaced, what's to stop the new cells from swelling? This PC runs hot, and heat shortens battery life. Would slowing the CPU clock help? Has anyone modified the charge controller circuit or its programming, to prolong battery life*, e.g., lowering the charge current, lowering the cut- off voltage to 4.10 or 4.05 instead of 4.20V?

I don't care if the time between charges is shorter. I keep it plugged in

99.99% of the time.

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Thanks for any helpful advice! - Rich S.

Small computer repair shops do these all the time, so they don't need to refer to detailed instructions as they work - it's a very quick job for them, and so it doesn't cost much. Some might over-charge, so get some quotes, but seriously - get it done by one of these and save yourself the hassle.

That's what I did anyhow. They said it would take 45 minutes but was done in only 25, while I wandered the shops nearby.

Clifford Heath.

An offie context is one thing. IIRC, there was an airplane that had batteries which developed bulging batteries. The 787.

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Paul Hovnanian     mailto:Paul@Hovnanian.com 
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Yes, I'm into fitness. I'm fitness whole taco right into my mouth.