Exploding pagers injure hundreds in attack targeting Hezbollah members, Lebanese security source says

[Disaffected]

118. That's not sufficient to explain

the rapid series of detonations - the detonations would almost certainly be more spread out if a manufacturing defect was at fault.

As well, as pointed out by others here, lithium batteries do not typically "explode" when they fail, rather they smolder and/or burst into flame.