Swelling battery

This is true, LI/LIPO batteries can swell slightly under what would be called "normal" operation. In fact as part of the manufacturing process LIPO (Lithium Ion Polymer "Pouch") batteries are often actually designed as a two-part pouch. The main part of the pouch is the actual battery, but there's an additional portion of the pouch that is left there to collect any excess gasses produced during the initial charging process. Once the manufacturer has completed the manufacturing and charging, that excess portion, a gas reservoir or "balloon" is sealed off from the main battery and then cut and removed, completing the manufacturing process.

As said by BatteryUniversity.com, sometimes these batteries will still swell slightly during normal charging/use, but if it swells beyond the compartment or area inside the device for which it's manufactured (like if the case will no longer shut properly or bursts open at the seams), it should be considered defective and then should be replaced.

 

I have also posted exploding batteries in the forum, and there is no question it happens - even under "normal" use. There are plenty of reports of people suffering burns and more as a result of this kind of failure. So to reiterate, I agree with you - to a point. These batteries can swell up to 10% of their dimension in thickness under normal operation and cause no undue risk. From BatteryUniversity.com (http://batteryuniversity.com/learn/article/types_of_battery_cells);

[h=2]Pouch Cell[/h] In 1995, the pouch cell surprised the battery world with a radical new design. Rather than using a metallic cylinder and glass-to-metal electrical feed-through for insulation, conductive foil tabs welded to the electrode and sealed to the pouch carry the positive and negative terminals to the outside. Figure 5 illustrates such a pouch cell.
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[TD] Figure 5: The pouch cell
The pouch cell offers a simple, flexible and lightweight solution to battery design. Exposure to high humidity and hot temperature can shorten service life.
Courtesy of Cadex
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The pouch cell makes the most efficient use of space and achieves a 90 to 95 percent packaging efficiency, the highest among battery packs. Eliminating the metal enclosure reduces weight but the cell needs some alternative support in the battery compartment. The pouch pack finds applications in consumer, military, as well as automotive applications. No standardized pouch cells exist; each manufacturer builds the cells for a specific application.
Pouch packs are commonly Li-polymer. Its specific energy is often lower and the cell is less durable than Li-ion in the cylindrical package. Swelling or bulging as a result of gas generation during charge and discharge is a concern. Battery manufacturers insist that these batteries do not generate excess gases that can lead to swelling. Nevertheless, excess swelling can occur and most is due to faulty manufacturing, and not misuse. Some dealers have failures due to swelling of as much as three percent on certain batches. The pressure from swelling can crack a battery cover, and in some cases break the display and electronic circuit board. Manufacturers say that an inflated cell is safe. While this may be true, do not puncture a swollen cell in close proximity to heat or fire; the escaping gases can ignite. Figure 6 shows a swelled pouch cell.
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Figure 6: Swelling pouch cell
Swelling can occur as part of gas generation. Battery manufacturers are at odds why this happens. A 5mm (0.2”) battery in a hard shell can grow to 8mm (0.3”), more in a foil package.
Courtesy of Cadex
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To prevent swelling, the manufacturer adds excess film to create a “gas bag” outside the cell. During the first charge, gases escape into the gasbag, which is then cut off and the pack resealed as part of the finishing process. Expect some swelling on subsequent charges; 8 to 10 percent over 500 cycles is normal. Provision must be made in the battery compartment to allow for expansion. It is best not to stack pouch cells but to lay them flat side by side. Prevent sharp edges that could stress the pouch cell as they expand.

 

I had a battery for a DX2 almost blow up in my face..... it was like a bad scene from 1000 ways to die. I make my living in the entertainment industry.... had that happened and i survived, It would've been a game changer for me.

Obviously it took the phone with it..... I quickly upgraded from that phone. It wasn't the phones fault though. I later learned that SOMEONE cooked my battery unintentionally.... I now sleep with one eye open.

Just had to throw this in though.

To clarify, it blew up seconds after I pulled the phone away from my face because it got suddenly hot...

DROID RAZR MAXXAMIZED!!!

 

My wife had set the battery on top of a hot cookie sheet. Then neglected to tell me. Hence the "sleep with one eye open" joke. It was my spare battery.

DROID RAZR MAXXAMIZED!!!

 

Did the trick in freaking me out. Perhaps my wife is trying to take me out....#looking around the room very suspiciously....... lol

DROID RAZR MAXXAMIZED!!!