Yesterday my friend's HTC sensation battery exploded like a bomb and was going to start a fire
and looking to other sensation users it looks that its a common problem if you put the phone
on charge for more than 5 hours.
What happened to the phone?

PS: Could it be a counterfeit battery?
I keep my phone charging overnight from 10 pm to next morning 9-10 am. Never had any similar issues like that.
Have a sensation xe and keep it charging overnight too, never had that prob.
I had mine for 4 months and nothing happened but my friend had it for 2 weeks today he show me his battery transformed into a ball , but thankfully the phone is okay only needed some cleaning.
GOOGLE search revealed that it's not the only case
http://forum.xda-developers.com/showthread.php?s=1872c54cd622057311379eb71369c1eb&t=1514929.
http://www.neowin.net/news/htc-touch-pro-battery-explodes-the-trend-continues

this one made afraid of sleeping with my phone near my head as most people do :-/
http://www.androidauthority.com/busting-the-myth-yes-cell-phones-can-explode-42582/

maybe its a power bug in some versions.
mine has a label saying "made in china" but his had a label saying "made in Taiwan" :-p .

viva china :-) .
That's weird, I've had my Sensation for 5 months, every night I charge it all night besides my bed. And I never noticed any overheating.

But to be on the safe side, I'll start charging it a bit further from my head.
Must be a fake battery,some Lebanese shops repalce original with fake to sell it for less
overclocking the CPU could cause the battery to meltdown i have heard .
Or bad charger...
I used to charge with an iphone AC/USB adapter but the screen was buggy because of it and the battery was getting unusual hot.
I am only using my PCs USB host now and the original HTC charger of course
Lithium based batteries are so dangerous (fire,injury,...), to make them safe in a mobile phone each one has its embedded monitoring circuit , so the problem can be 90% bad/fake battery or bad luck :-( .

to check this out my friend changed the battery but he didn't change the charger nor the phone so if nothing happens it will be a fake battery.
5 days later
For any one interested in a new htc sensation battery , the replacement battery had ~1740mA capacity, that is ~300mA charge more than the old one so i think more battery time without any noticeable weight increase, i am jealous ;-) , i will wait and see if it's working for him i may think of buying one .
You had opened this thread to point out the danger of Lithium ion batteries, and you're thinking of buying a non-official / 3rd party battery? I will try to explain from what I know:

Every battery technology has a number called charge per kg. It is high for Lithium batteries, meaning that Lithium batteries store more charge for less weight. The thing is that limitations in battery capacity are chemical. They cannot simply be made to have more capacity for less mass of lithium. This can mostly be done by REDUCING THE THICKNESS OF THE WALLS THAT COVER THE LITHIUM CELLS. Meaning, the battery is more fragile. It can crack more easily (pressure or I guess heat). And when this Lithium is exposed to air, it can explode, burn, cause injury...

3rd party batteries, if from non-reputable (EVEN IF from reputable) manufacturers should be avoided at all cost! And the ratings, when too high, are usually false. Sure, they do offer a bit more capacity, may be slightly thicker, I don't know, but if it's not manufactured with proper guidelines, it can be dangerous.

Sony had a recent fiasco in 2006. The production of batteries left bits of metal in the Lithium cells. When exposed to heat, many batteries exploded or caught fire. A few cases, and Sony had to recall millions of Lithium batteries for laptops from Apple, Dell, HP (I think).

Beware!
@yasamoka first I'd like to thank you very much for this valuable information and i agree with your point 100% but also it could be a real genuine battery.
and you're thinking of buying a non-official
the battery has the htc logo and all the tags "ce,..." + serial numbers+... , so it looks official and I'll wait for a while before i MAY buy one .
They cannot simply be made to have more capacity for less mass of lithium.
It might be heavier but the increase in capacity isn't large so the weight increase could be unnoticeable (i didn't use a scale)
This can mostly be done by REDUCING THE THICKNESS OF THE WALLS THAT COVER THE LITHIUM CELLS. Meaning, the battery is more fragile. It can crack more easily (pressure or I guess heat). And when this Lithium is exposed to air, it can explode, burn, cause injury...
and you know that technology these days is a fast developing environment so i thought that it may be a new development in battery technology or fabrication.
Beware!
don't say that to me :-) , i've lost around 4000$ because of a single 7$ lithium-ion battery left on charge during the night (the charger was a simple power supply ) the whole room turned black and the contents into ashes :-(, from that accident till now i charge any unattended battery inside a metal box.
@solo-220: OUCH! the more I hear about Lithium batteries, the more I go crazy.

I wanted to actually share a full post about the issue of Lithium batteries in Lebanon, but haven't had the time to do (remind me if I forget please). I will share a bit, I guess: can you tell, whether each of these batteries is official or not, and why:



@yasamoka

i was going to send you an email but i got a notification that your inbox is full...
The second one has a weird date "11-11-2011" but i like it when the battery has a manufacture date label .
Solo-220: What do you think? Is the first battery genuine or fake? Is the second battery genuine or fake?
Another matter electricity in Lebanon and temperature.
LiPol and LiIon doesn't like high temperatures. Also it is difficult to imagine that someone will unplug charger and plug back when battery full, but because EDL/Ishtirak switch a lot, it can overcharge battery.
I'd say #2 is counterfeit because:
1- Serial number is shorter
2- "Date" label is in chinese. Besides, I don't think there is any use for printing the date at that place
3- Typography and some of the graphic work is lower quality (fonts, alignment of text...)
and as someone pointed out the date is weird, but it could be a coincidence.

It's just a guess, and I'd have to look up the model number on the internet to see if I'm right.