The advanced battery packs today are "part of the frame", an integral part, it would be tough to swap them out and maintain frame stiffness without weight gains.
GM’s purpose-engineered ‘skateboard’ EV chassis uses the huge 24-module Ultium battery pack, rather than a ladder frame, as its foundational structure. That makes it “extremely stiff” in bending and torsion, Kraatz noted. Combined with Silverado’s independent suspension the skateboard structure benefits ride/handling and simplifies GM’s bill-of-material and in-plant complexity, at the expense of customer choice. The industry will be watching which EV pickup strategy, GM’s or Ford’s, proves most profitable over time.