Abstract: A battery assembly includes a battery module stack in which at least one battery module is stacked and formed, a cover portion coupled to a side of the battery module stack, and a substrate portion coupled to an external surface of the cover portion, wherein the cover portion includes a cover member coupled to the battery module stack, and a protrusion member protruding in an outward direction from the cover member and in contact with an internal surface of the substrate portion, the substrate portion includes an overlapping region which is a region overlapping the protrusion member when viewed in the outward direction, a through-hole passing through the overlapping region in the outward direction is formed in the overlapping region, and a pad region having electrically conductive properties is formed in a region surrounding the through-hole in the substrate portion.