Manufacturing defects, internal insulator leaks, can also cause a LIPO to fail EVEN THOUGH it has been properly used and maintained. Multi-cell LIPOs, like the 4S types used in the Typhoon H and H520, typically have more potential for failure than single cell types such as the ST16 battery.
For the Typhoon series and the H520, if a battery you have been using becomes more difficult to insert (usually after storage), it is a sign of swelling. This may happen even though you had discharged it to the safe voltage before storing. BEWARE, the safe thing, even if it is holding a good charge, is to dispose of it.
LIPOs are safe when handled correctly, charged, used, and stored according to the manufacturer's recommendations. If you are new to LIPOs, know that they are not like the usual off-the-shelf batteries. Take time to study and understand how to handle and use them; keep them in fireproof containers out of temperature extremes.
If you choose to use a LIPO battery with a different connector, TAKE EXTREME CAUTION to see that the two battery leads never touch when exposed. Plan ahead careful steps to avoid this possibility.
This short video is not recent, but it demonstrates the explosive and fire potential of LIPOs overcharged beyond their designed capacity. Of course overcharging is not the only way LIPOs can fail.