You can tell the battery manufacture date by looking at the 4-digit number on the upper left of the battery label. The number is listed as Week-Year (WWYY), so “3213” was manufactured in week #32 of the year 2013.
Batteries are a consumable and carry a 1-year warranty.
Purchase replacement batteries: LabQuest® 2, LabQuest Stream™, and Go Direct SpectroVis Plus Battery (LQ2-BAT)
How old is my LabQuest 2?