A storage device for battery modules includes a housing made up of outer walls, inner walls between the outer walls, and bridge walls connecting the outer walls with the inner walls. The inner and outer walls define through holes, each configured to receive a battery module therein. The housing defines several fluidly isolated air flow spaces. The device also includes fins, each protruding from one of the bridge walls and blocking a portion of one of the flow spaces. An alternative storage device for battery modules includes a housing made up of outer walls and inner walls between the outer walls. The inner and outer walls define through holes, each configured to receive a battery module therein. The housing defines several fluidly isolated air flow spaces. The device also includes fins, each blocking a portion of one of the flow spaces and connecting the outer walls with the inner walls.