I have like 53 of these empty ones, I check the yard to charge them but the NPC keeps telling me its broken.
Been that way for a week now, is this bugged or am I just at the mercy of more RNG to upgrade my essence?
Check the engineer siblings for the “Energy Cells for Everyone!” daily, it will tell you if the Charging Station is even available that day.
Besides that, rares and mechanized chests can drop charged cells, and some dailies (typically from the engineer siblings) will offer one as a reward.