Lattepanda Sigma Battery Powered + GPU?

Hey guys, I'm just wondering if the lattepanda sigma supports battery power, any if so, if there are any examples of batteries that support it. I'm also wondering if it'd support a discrete graphics card through the NVME PCIE 4.0 X4 slot, and how much power it'd provide?

I'm thinking about making a DIY handheld-like thing and obviously it'd need to run off a battery