They seem to be armor plating that uses batteries as hp, but there seems to be no point as they will get rekt by some megaton cannons, cruise missiles, or even rockets with BASIC explosions(eg venture missile pods). We honestly don't need heavy armor as it stands in the current meta, so the entire point of the RR shields is basically some 'backup' armor in case of a small tech breeching your shields, which when used under shield bubbles, causes more battery drain for no more protection.