I don't see how it could happen, either. It's not enough to strike a .22 on the rim, there has to be something to strike against, i.e. it's a hammer-anvil effect. The firing pin hits one side of the rim while the other side is supported against the edge of the chamber. The firing pin crushes the priming compound between the brass lips of the primer.

The batteries? There's an electrically primed muzzleloader on the market, but that's black powder with an ignition system designed to set it all off.