This just goes to show that if batteries don't have the correct saftey tests the results can be explosive.
We recieved this battery back in our returns by someone claiming it to be ours. The battery was unbranded and showed no resemblance to ours. It had overheated in the charger and exploded, ruining the battery and the charger and luckily nobody was injured, but it just goes to show how dangerous these things can be if they're not checked for safety.
If you're going to buy a cheap product make sure it has the correct safety markings, like CE Approved, and it is branded with the company's name.