A crossmember for a vehicle battery tray provides a beam that has a closed cross-sectional shape with a top wall coupled with parallel side walls along a length of the beam. A reinforcing top cap is disposed along the beam, where a C-shaped transverse cross-sectional shape of the top cap has a central section that disposed along the top wall and legs of the top cap welded to the side walls. The legs include inward angled tabs that are biased against the beam and welded thereto. The top wall of the beam and the central section of the top cap have aligned fastener openings disposed at spaced intervals along the length of the beam and configured to receive fasteners that secure at least one of a battery module or tray cover to the crossmember.