This is a battery holder for 3 cells of 18650 that goes along with these pins from AliExpress (https://nl.aliexpress.com/item/1005004432819933.html?gatewayAdapt=glo2nld). Just solder the pins to a PCB and then stick the holder on top, no glue needed. After inserting the 18650 the battery holder holds itself on the board.
The author marked this model as their own original creation.