Usually Lenovo sytem recognizes non Lenovo genuine battery and informs the user in Power Management (PM) application (in case of win7 is running). Also, it's possible to identify such battery by its data PM provides and the information on the battery sticker.
x220 • Gobi 2000 3g | hdd, msata ssd, wwan, wifi, gps -- unique hand-made config ThinkPad 25 Special Anniversary Edition. #retro. Signed by D.Hill T470p | X1 Carbon Gen3 | Miix 2 10" | Yoga Tablet 2-1050F (Android) + BT Keyboard ThinkPad Stack • 2.4/5 Wireless Router, HDD 1 TB, BT Speaker, Power Bank, Mobile Projector