Sewable CR2032 Battery Holder
his holder is meant to be used with Lithium CR2032 (20mm diameter, 3.2mm thick) sized coin batteries. These are almost always 3V at about 200+ mAh capacity. Lithium coin cells are not rechargeable but they are very easy to find, available at any grocery store.
Inserting the coin is easy, the holder is very sturdy, and it snaps out with a push. Its got a nice flat plastic back that you can easily glue in place for extra mechanical stability.
Datasheet with measurements