Power Cells are a consumable power storage item. Once crafted, they provide power to whatever they are attached to. Once all 8 cells are depleted, the Power Cells will be destroyed.
Power Cells cannot be recharged, and instead evaporate once depleted.
Trivia
Power Cells discharge to the player's backpack automatically if it isn't already full.
Due to their small size and relatively high energy density, a single Power Cell can fuel a Buggy for 42 minutes. They aren't useless on Medium Rovers, either being able to power them for 96 seconds or 1 minute 36 seconds using only one power cell meaning the white and yellow circles.