Integrated battery case

An integrated battery case includes an intermediate panel provided under a plurality of battery cells and configured to cool the battery cells; a cooling channel member provided under the intermediate panel and including channels formed in an internal space of the cooling channel member; and a lower cover provided under the cooling channel member, including a composite material-based double layer to protect the battery case when a collision occurs in a lower portion of a vehicle, and integrally connected to the intermediate panel and the cooling channel member by a plurality of mounting portions and a through portion.