hi! I have been breaking my head about this:
searching for a movie, I only remember that there is a small battery, hidden inside a toy-puppet, sort of lego figure. Inside there is a powercell that has enough energy to power up big citys. Two people designed the powercell, one good guy that has it now. And one person that wanted to sell it to ‘bad’ people. In the end it gets blown up in a helicopter (it was stolen by some bad guys).