A battery pack and a vehicle, wherein the battery pack includes a box assembly, a battery unit, a constraint component and an outer cover, the box assembly includes a box body and a fixed beam, the fixed beam is fixed in the box body; the battery unit is arranged in the box body; the constraint component covers the battery unit and is fixed with the fixed beam; and the outer cover is arranged on one side of the constraint component away from the box body to seal an open end of the box body.