I was thinking about water and ice. Since ice when it melts looks like some kind of 3D printed structure. I wondered. What inventions have a 3D printed ice structure? A 3D printed refrigerator maybe.
Then out of nowhere. Could a battery cylinder with a hole in the middle regulate its temperature much more efficient? Like a warm blooded battery perhaps. Instead of regulating the outside. You can just heat or chill from the inside. Should give a more even result.