from stainless steel alloy while the electrolyte 20 is made of a mixture of alkali halide salts of course there are numerous other combinations of materials the actual chemical makeup of the cells is not a critical to the invention thus the cell structure need not be discussed in further detail referring back to fig1 the cells are connected in series by the conductive spacers 22 non conductive spacers 23 a and 23 b further insulate the battery cells 14 a 14 h from the top and bottom covers 13 a and 13 b of the housing 11 lead wires 24 and 26 connect the cells 14 a 14 h to connectors 27 and 28 mounted in the in the top and bottom covers 13 a and 13 b respectively of the housing 11 these lead wired 24 and 26 also extend through holes not shown in the spacers 23 a and 23 b and top and bottom covers 36 a and 36 b respectively of the container 32 the plurality of battery cells 14 a 4 h are placed under compression and wrapped with an inner flexible high temperature insulation layer 30 a suitable high temperature insulation material is fiberflax u00ae manufactured by unifrax corporation niagara falls n y.