A battery module includes a module including a series of cell stacks, each having a series of unit cells arranged in a first direction, and an insulation member insulating at least one unit cell. The battery module also includes a module housing and a series of receiving parts in the module housing accommodating the cell stacks. Each receiving part includes a fixed wall around a respective cell stack and having a portion in contact with the cell stack. The fixed wall includes a pair of end walls at opposite ends of the receiving part in the first direction. The pair of end walls are configured to engage respective end surfaces of the corresponding cell stack in the first direction. The battery module also includes a cooling channel below a floor surface of the module housing for a coolant to flow to cool the receiving parts and the cells stacks.