The battery for the HP EliteBook Folio 9470m and 9480m is officially known as the BT04XL (or BA06). It is a thin, internal Lithium-ion (Li-ion) battery with the following specifications:
Voltage: 14.8 V
Capacity: 52 Wh (Watt-hours)
Cell Count: 3 or 4 cells (depending on the manufacturer)
Average Run Time: Approximately 3 to 7 hours depending on your screen brightness and usage
Recharge Cycles: Designed to last around 500 full charges before wearing out