I liked the design of Nodashi's battery holder, but wanted it to be just a bit slimmer.
No supports needed. Printed upright on a Bambu Labs P1P with SUNLU black PLA at 0.2mm with 2 wall loops, 10% gyroid infill.
Edit: Updated to v2 so batteries no longer get stuck, requiring a bit of a push to unjam them.
The author remixed this model.
Slimmer model (thus holding a few less batteries), raised the hopper door, adjusted the angle of the hopper feed, and slimmed the back wall for a low-profile version.
Edit: Updated, previous version batteries would sometimes get stuck and need a push.