a first lower wall configured to support a first cell stack; and

a pair of first cross members spaced apart from each other in a longitudinal direction of the electric vehicle, each first cross member providing lateral support for a respective side of the first cell stack and configured to extend substantially an entire width of a battery enclosure,

wherein each first cross member comprises an outer wall, an inner wall spaced apart from the outer wall, and connecting members, the outer wall, the inner wall, and connecting members cooperate with each other to define an internal cavity, and

wherein the inner walls of the first cross members are secured to the first lower wall and slidable relative to the outer walls of the first cross members.