Did you mean to say you are working on a project or that the link is a working project? Because (a) 115.9V is some no-kidding-don't-touch-the-wrong-wire (b) that linked page cites a bunch of extra thermal management stuff which presumably its source EV managed but in any such home setup someone else is going to have to manage
The link is one of the batteries im using in a project for home power wall. You are correct, 100+ volts, and 1000+amps and fire if things go wrong is no joke. Im EE so doesnt make me fire proof but can appreciate the scope of the safety measures required for the project.