You can use AAA batteries instead of AA by placing a small piece of tinfoil in the gap. : r/lifehacks
Test of Aerocell AAA
The Coffee Must Flow: Replacing A Spent Lithium Cell In A Coffee Machine | Hackaday
Aerocell batteri - Lidl Sverige - www.lidl.se
Bag of Small Domestic Dry Cell Batteries, Old Trash To Recycle. Isolated on White. Alkaline . Europe, UK AA and AAA Size Editorial Stock Image - Image of discarded, electric: 144020719