[satiric]

Plugs and sockets have the wrong gender for this. On the battery, you'd have a male plug with live 240v contacts, ready to short against anything, or anyone, that's conductive. This is the same reason why male-to-male extension cords are labeled "suicide cords".

[gambiting]

Well, yes generally speaking. But the way this works with these plug in panels is that the micro inverter won't actually start delivering power to the grid in the absence of an energised plug in the first place. So just sitting there, the contacts are completely harmless. Obviously actual physical safety where you literally can't touch the contacts would be better.

[satiric]

How do you detect that it's plugged in? Just detecting voltage would mean that you'd unplug it and it would stay energized, right?

[hnaccount_rng]

They need the grid frequency to generate AC. Those inverters are only allowed to be grid-following (at least for the plug-in part. I think there are systems that provide a -to-load socket that can be a PSU)