Battery tray, battery pack and vehicle

The utility model relates to a battery tray, a battery pack and a vehicle. The battery tray comprises a cold plate used for bearing a battery cell, an expansion beam is arranged on the cold plate, the battery tray further comprises a connecting piece, the expansion beam is connected with the cold plate through the connecting piece, and a brazing layer is arranged between the connecting piece and the cold plate. According to the technical scheme, the connecting piece can be connected with the cold plate in a brazing mode, and the welding mode has the advantages that the cold plate serving as one of welded components is not affected, so that a runner in the cold plate does not need to be avoided in the brazing process, and the connecting strength between the connecting piece and the cold plate is guaranteed. And furthermore, as a runner in the cold plate does not need to be avoided when the expansion beam is mounted, the setting position of the expansion beam can be selected without limitation according to the