[premchai21]

Electrolytic capacitors are capable of popping violently should they become internally shorted by excessive overvoltage or reverse bias. The aqueous electrolyte destabilizes and produces hydrogen, which builds up pressure inside the casing until it leaks or blows. Dramatic video: http://www.youtube.com/watch?v=ToWsF3HcQUU

I can vaguely imagine a charging circuit being designed to have what amounts to a current source rather than a voltage source, but I don't know enough in detail to confidently associate that idea with the story in question.