Exploding cordless drill battery pack

My 2-yr-old el-cheapo B&Q "Performance" cordless drill finally gave up the ghost yesterday in a most spectacular fashion - one of the battery pack cells exploded with a loud bang, black confetti, and lots of plastic shrapnel flying off around the garden. Fortunately no one was injured (might have been different if I was working inside).

At the time I wasn't doing anything above what I've been using it for already (in this case driving a screw into a wooden fencepost). It was not fully charged, so unlikely to be related to overcharge from temperature drop (it wasn't that cold yesterday) so other than component failure I'm at a loss as to the cause.

Anyone heard of this before? Is it a condition that only the cheap tools suffer from, or do 'big-name' brands (Makita, Hitachi, etc) also suffer this alarming failure mode?

I think my dalliance with cheap tools is over.

Cell must have internally shorted.

Most likely, agreed. Of course, all the cells were unbranded so no chance of tracing them... other than the (obvious) country of origin

Yeah. It happens.

I had a 36volt one blow itself to bits on me.

Good news is B&Q replaced it no problems.

Bad news is that one blew up too...

Well, my old exploding one was itself a shop replacement for a previous B&Q cheapo model that just stopped (suspected open-circuit battery that time), and well outside of its return period so its in the bin now.

Treated myself to a Makita courtesy of B&Q's current half-price offer. I hope it will last a good deal longer!