Something like this

SDTC Tech 8-Pack 3.7V 18650 Battery Holder with Soldering Pins 1/2/3/4 Slot Black Plastic Battery Case Kit for DIY Parallel or Series Circuit PCB Projects(2 Per Size) https://www.amazon.com/dp/B0858ZKCHZ/ref=cm_sw_r_cp_api_i_NfQnFbDPKGJP2