A long time ago, I discovered some quasi-AAAA cells inside 9 V batteries:
It occurred to me that I should dismantle a defunct Rayovac Maximum 9 V alkaline battery from the most recent batch (*) to see what it looked like:
A closer look at those pancake cells:
They look like separate cells bonded into a stack, although there’s no easy way to probe the inter-cell contacts; the leftmost cell probably died first.
(*) Which has apparently outlived the Rayovac Maximum brand, as they don’t appear on the Rayovac site.