Batteries???

So with the addition of lightning rods that can power redstone signals, why not add a way to store that power and lug it around with you?
That leads me into presenting a battery! (which this sentence is kinda redundant since I just introduced it)
And it doesn't even have to be called a "Battery", one name idea could be "Electric Sponge" and you could make a cool design based off of it.
And it would take energy from lightning rods, and it could have some sort of visual indicator.