A container for a battery is disclosed. The container includes first and second side walls coupled to end walls and a base forming a recess. The side walls and end walls each have an edge. A container intercell partition wall is provided in the recess and has a segment which extends above the edge of any one or more of the first side wall, second side wall, and end walls. A cover is also provided having a cover intercell partition wall with a recessed area which accommodates the extended segment of the container intercell partition wall. The cover intercell partition wall may be coupled to the container intercell partition wall by a heat seal. A method of assembling a battery container is also disclosed.