296
This 9v battery contained six cells stacked like a layer cake
(lemmy.sdf.org)
Picture of a disassembled Duracell 9v battery. Below the terminal assembly is a clear plastic case where you can see six sets of stacked rectangular terminals and fillings.
The metal shell is part of the protection.
Who needs protection when you have cool lookin batteries?
Jokes aside, maybe a print of how the insides look would be cool, too. Like the phone cases from that recent JerryRigs drama.