Li-Ion 24 V battery built from 98 cells 5000mAh 3.7V Rechargeable 18650. The specs and price can be found here https://www.garberiel.com/products/10pcs-5000mah-37v-rechargeable-18650-batteryyellow?VariantsId=10833
You need only to solder the battery management system, a brand new electronic board that will be included for free and you will have a new powerful battery.