When entering the large cavern with the precursor robot in Spider Cave, hold a left and continue past the bottomless pit. At the end here you'll find a precursor platform and some blue eco, take the platform down and subsequently use the launcher hidden away here to launch yourself back up. You'll end up at a total of 16 swinging poles (4 by 4) and a bunch of Precursor orbs and some blue eco.
From here go swing and jump left while making sure to be channeling blue eco, you'll see another precursor platform which will be activated when you jump onto it. It'll fly up and bring you next to a power cell.