Lihzahrd Power Cells are used at a Lihzahrd Altar located at the end of the Lihzahrd Temple to summon the Golem boss. One is found within each Lihzahrd Chest. They also have a 1/50 (2%) chance of dropping from Lihzahrds and Flying Snakes. A single Cell is required for each summoning of the Golem. In the Mobile VersionTemplate:Mobile icon, the power cells can also be crafted.
Lihzahrd Power Cells can only be used in worlds where Plantera has been defeated, otherwise the summoning will fail, and the item will not be consumed from your inventory.
Template:Console icon On the (current) console version it is possible to use Lihzahrd Power Cells to summon the Golem without having killed Plantera.
Tips
With extra Temple Keys or a Picksaw from Golem, Power Cells can be farmed by generating new worlds and gathering the cells guaranteed to be in their Temples' Lihzahrd Chests, rather than having to kill Lihzahrds hoping for drops. Golem can only be summoned in a world where Plantera has been defeated, so Cells gathered this way will need to be used in your other world.