Small battery clip.
It's light and holds the battery firmly.
I would advise you to gule a sheet of thin EVA on the botton plate, to prevente the battery from sliding while flying.
Print wihtout support. I have used ABS, with 0.2mm layers and no infill. You may try another settings/materials.
Please, share it if you print it!
EDIT: added two more versions for different battery sizes. original is 15mm
These will also fit the papacapim 105 micro drone (https://www.thingiverse.com/thing:2608429)