Quite honestly, this laptop is not too far from being an ordinary business notebook. However, it supports up to 64GB of DDR4 memory in dual channel, which is still something rarely seen on the market.

1. Remove the bottom plate

In order to make changes on the inside of this device, you have to undo 9 Phillips-head screws. They stay attached to the bottom panel even after you unscrew them, which means it would be difficult to lose them. Before starting the prying process, make sure you remove the SIM card tray.

2. Battery

Unfortunately, the 45Wh battery pack in this notebook is glued to the chassis, in addition to being secured by three Phillips-head screws. We don’t really see a point of Lenovo doing so, other than preventing customers change their batteries, should the die after the warranty period ends.
…
Read full post here:
https://laptopmedia.com/highlights/inside-lenovo-thinkpad-l15-disassembly-and-upgrade-options/