A vehicle battery tray has a floor assembly with elongated tray sections that attach together at edge portions of adjacent tray sections of the elongated tray sections to form a floor structure that supports vehicle batteries contained in the vehicle battery tray. The elongated tray sections may have substantially consistent cross-sectional shapes that extends along a length of the tray sections. A thickness of the tray sections at a central area of the floor structure may be greater than a thickness of another one of the elongated tray sections at an outboard area of the floor structure, such as to withstand an equal or greater transverse bending moment than the outboard area of the floor structure.