Lenovo ThinkPad T420si (English) User Guide - Page 114

To replace the battery with a new one, read the following prerequisites, and select your model from the list below for the instruction. Prerequisites for the procedure DANGER If the rechargeable battery pack is incorrectly replaced, there is danger of an explosion. The battery pack contains a small amount of harmful substances. To avoid possible injury: • Replace only with a battery of the type recommended by Lenovo. • Keep the battery pack away from fire. • Do not expose it to excessive heat. • Do not expose it to water or rain. • Do not short-circuit it. • Do not drop, crush, puncture, or subject to strong forces. Battery abuse or mishandling can cause the battery to overheat, which can cause gasses or flame to "vent" from the battery pack or coin cell. Replacement instructions To replace the battery, do the following: 1. Turn off the computer, or enter hibernation mode. Then disconnect the ac power adapter and all cables from the computer. 2. Close the computer display, and turn the computer over. 3. Unlock the battery latch by sliding it to the unlock position(1). Holding the latch in the unlocked position, remove the battery (2). 98 User Guide