Li-on 18650B with Protection Board is longer than standard li-on 18650B. I used contacts on basic holder from AliExpress.
Li-on 18650B with Protection Board
https://www.aliexpress.com/item/32611589032.html
Standard Battery Holder for Li-on 18650B without Protection Board
https://www.aliexpress.com/item/33031081402.html
PCB (possible download from here for other project)
https://www.fstimer.cz/wiki/doku.php?id=optobrany_-_mala_casomira#plosny_spoj_opt_20
The author marked this model as their own original creation.