This is a minimal battery holder for an 18650 cell.

Dimensions are optimized for a 0.4mm nozzle and 0.28mm layer height.
Recommended print settings are 4 walls, 0 top/bottom layers and 0 infill, but it should be fine with standard print settings.
Ideally position the seam where it doesn’t interfere with the fit between the parts and battery.

After printing just thread electrical wire through the holes and wrap it around each tab to finish.

Update 2026-05-23: Improved first layer adhesion success rate and improved fit between components and battery.