connected over the other end cell module 23 once compressed the shrink wrap can be shrunk for example via a heat gun so that the shrink wrap material shrinks in the direction of the axial center of the stack to a new position as wrap 50 a the shrink wrap 50 a overlaps the end plates 51 52 and thus retains compression of the interconnectors 24 spacing or connections for electrical feedthroughs 21 may also be provided prior to shrinking or post shrinking if desired the wrap 50 a preferably is spaced from the peripheries of the interconnectors but contacts the peripheries of the cell modules 23 the shrink wrap material 50 should have electrically insulating properties if the shrink wrap material makes or becomes in contact with the interconnector 24 if the interconnector 24 is not itself electrically insulated at its periphery the shrink wrap material 50 would beneficially be thermally conductive more than 50 cell modules may be wrapped and preferably at least 20 the embodiment of fig1 provides a cost effective and simple manner for compression of the stack of cell modules as well as hermetically sealing their enclosure the shrink wrap also may reduce the weight of the cell stack and can be used efficiently in mass manufacturing instead of a heat gun the cell.