That sucks, Edy. Same thing happened to a friend of mine. Lucky for both of you the phones weren't in your pockets when this happened. lol
Yes tell me about it. I was a bit stunned to see the phone in that shape when I pulled it out my bag. I was thinking, did one of my kids grab this thing and drop it on the floor, and then stick it back in my bag? Did I bump my bag or do something without knowing? This phone (iPhone 4s) was being used as a back-up just to connect to WiFi and get Podcasts and News and eMail. I would charge it maybe once a week, it was just something I could glance at or give my kids if they wanted to play a game. There was no SIM card in there.
A few years ago, the port on the bottom (those long 30-pin types) got messed up and the phone refused to charge. I tried different cables, nothing worked. I thought it was the battery (I did not realize the port was the problem) and ended up ordering the replacement battery first with the screwdriver kit for $8. In any case I needed the tools to get in (this was before I got my fancy precision screwdriver set). I kept the ORIGINAL Apple battery just in case.
Then after I replaced the Apple battery with the OEM one that came with the toolkit (like shown above) and it still didn't charge, I looked with a microscope at the 30-pin connector and noticed a couple leads missing copper. So then I went back on eBay again and ordered the 30-pin dock connector for the 4s for maybe $2. It was cheap, looks like this:
After replacing the dock connector, put back the OEM battery since I figured I may as well use it ANYWAYS as I already bought it (nothing wrong with the original Apple battery as far as I knew), I was able to charge up fine and the phone worked great and lasted for days on a single charge (with my light use) and had no problems at all.
Fast forward a year or two and all was going fine until this incident I noticed yesterday. It could have busted open over the past few weeks, I don't even know as I didn't play with the phone for that long. There is absolutely no physical sign of any damage otherwise whatsoever, it all happened from inside the case. Something happened to make the battery vent gas and swell up.... Remember it was not being charged at all, in fact the charge was probably very low but enough to power the screen enough to show me the iPhone needed to be charged... as you see in the first part of my video... the grossly swollen battery was actually still functioning!
Remember I didn't throw out my original Apple battery, it was just laying around discharging slowly over the past 1-2 years, that's what I used as a replacement in the video. It works great, and hopefully the original Apple battery is built to better standards and won't do the same thing! Although now Apple did some software updates because it knows there are some problems with the older batteries and changes the speed of the phone or discharge rate or something. This phone is on an old iOS version that is not going to get updates ever again (it's on iOS 9.3.5 and it says it's up to date when I check so looks to be abandoned by Apple).
Spontaneous reaction? Strange... Scary. How can you ever know you are buying a "legit" battery now unless you get it from the original company, and even then some of the older models they don't even have stuff for anymore and they send you to some 3rd party OEM "fake" manufacturer.