Battery systems according to embodiments of the present technology may include a battery characterized by a first surface, a second surface, and a third surface. A recessed ledge may be defined by the third surface about a midpoint of the battery. The first surface and the third surface may define a first terrace formed proximate a first lateral edge of the first surface of the battery adjacent the third surface of the battery, and a second terrace formed proximate a second lateral edge of the first surface of the battery adjacent the third surface of the battery and opposite the first lateral edge. The recessed ledge may extend along the first surface of the battery between the first terrace and the second terrace. The battery systems may also include a module seated on the first surface of the battery between the first terrace and the second terrace.