Electrical cable or portable battery
I would love to see some kind of thick electrical cable to transfer energy. I know that this is possible via connectors. But, as an example, when you land on a planet with the atmo lander and want to save the energy from the batteries or rather transfer it to your newly built station, there hardly is a way to salvage the energy from the big batteries other than transporting the whole battery over or attach a connector to both lander and station (what if you already dismantled the thrusters from the lander and there is still tons of juice in the batteries left?).
Either have a blog like an electrical outlet for both sides (atmo lander and station) and then have a cable to connect the two to transfer the energy or: have some kind of stackable transportable battery to be able to transport the energy in tangible form out of a grid to a new one.
Probably the cable idea would be a bit more practical.