Abstract: A high temperature storage battery comprises a plurality of panels forming a housing defining a cell storage cavity, heat insulating material in or adjacent the panels, and a non-aqueous high temperature electrochemical cell within the cell storage cavity. It also includes holding means for holding a dispersable protective substance. The holding means is adapted to discharge protective substance into the cavity on the temperature in the cavity exceeding a predetermined temperature, and/or on rupturing thereof.

Abstract: A method of making a cathode for a high temperature rechargeable electrochemical cell comprises impregnating a mixture, in granular form, of an alkali metal halide and a substance comprising a transition metal selected from the group consisting of iron, nickel, cobalt, chromium, manganese, and mixtures thereof, with an alkali metal aluminium halide molten salt electrolyte. The impregnated mixture is subjected to at least one charge cycle in a high temperature electrochemical cell in which the impregnated mixture forms the cathode and is located in a cathode compartment of the cell. The cathode compartment is separated from an anode compartment by a solid electrolyte separator. Alkali metal forms in the anode compartment during the charge cycle.

Abstract: The invention provides a method of making a magnesium/aluminium spinel compound having the formula Mg.sub.(1+x) Al.sub.(2+y) O.sub.4 in which 0.ltoreq.x.ltoreq.0.2 and 0.ltoreq.y.ltoreq.0.35. Particulate aluminium metal and a magnesium-containing component selected from magnesium oxide and precursors thereof are mixed together and heated to 800.degree.-1150.degree. C. in an oxidising environment to cause oxidation of at least part of the aluminium. Further heating then takes place to a temperature of 1150.degree.-1350.degree. C. in the oxidizing environment to cause aluminium oxide and magnesium oxide in the admixture to react together.

Abstract: A method of making a .beta.-alumina compound which is a polyaluminate of the general formula M.sub.y O.multidot.xAl.sub.2 O.sub.3 in which M is a metal selected from monovalent metals and divalent metals, y=2 when M is a monovalent metal, y=1 when M is a divalent metal and x=4-12 comprises forming a green precursor of the 62 -alumina compound by mixing together particulate aluminium metal and a reagent compound comprising an oxide of the metal M or a precursor thereof. The mixture is heated to 800.degree.-1150.degree. C. in an oxidizing environment to cause oxidation of at least part of the aluminium. Further heating then takes place to 1150.degree.-1350.degree. C. in said environment to cause the oxidized aluminium and oxide of the metal M to react to form the .beta.-alumina compound.

Abstract: A high temperature rechargeable electrochemical power storage cell has an anode compartment and a cathode compartment separated from each other by a separator. The cathode compartment contains a current collector; an alkali metal aluminium halide molten salt electrolyte having the formula MAlHal.sub.4 ; an alkali metal halide; and a cathode. The cathode comprises an electrolyte-permeable porous matrix, a first active cathode substance in the matrix in a first zone adjacent the current collector and spaced from the separator, and a second active cathode substance in the matrix in a further zone adjacent the first zone. The first active cathode substance is such that it gives rise to a higher cell potential than does the second active cathode substance. The cell is chargeable at a temperature at which the electrolyte and the alkali metal are molten to cause the active cathode substances to be halogenated.

Abstract: A high temperature rechargeable electrochemical power storage cell has a molten sodium anode separated by sodium ion-conducting solid electrolyte separator from a solid cathode comprising an electronically conductive electrolyte-permeable porous matrix. The matrix is impregnated with a molten salt electrolyte, and has solid active cathode material dispersed therein. The molten salt electrolyte comprises a substantially equimolar mixture of sodium chloride and aluminium chloride. The active cathode material comprises at least one transition metal selected from the group consisting of Fe, Ni, Cr, Co, Mn, Cu and Mo having, dispersed therein, at least one additive element selected from the group consisting of As, Bi, Sb, Se and Te. The atomic ratio of transition metal:additive element in the active cathode material is 99:1-30:70, the cell having a charged state in which the active cathode material is chlorinated. The invention also provides a method of making such cell.

Abstract: A high temperature rechargeable electrochemical cell has a housing containing an anode and a cathode, and divided by a sodium ion-conducting solid electrolyte separator into an anode compartment and a cathode compartment, containing respectively molten sodium active anode material and active cathode material. The separator is tubular, having a closed end and an open end, and a plurality of circumferentially spaced radially outwardly projecting ribs or lobes. The housing is a tubular canister which is polygonal in cross-section, so that it has a plurality of circumferentially spaced corners corresponding in number to the number of lobes of the separator. The separator is concentrically located in the housing, each lobe of the separator being circumferentially aligned with, and projecting radially from the separator towards, one of said corners.

Abstract: The invention involves a method of making a holder of solid ceramic material by locating a core in a mass of particulate ceramic material, consolidating the particulate material around the core, removing the core from the particulate material to leave a green artifact having a cavity, and sintering the green artifact. The core is shaped and the particulate material is arranged such that the core is in the form of a thin slab between a pair of layers of the particulate material. After sintering, the cavity comprises a thin gap between opposed plates of sintered ceramic material. The slab has openings therethrough which are filled with the particulate material, which, after sintering, forms a bridge across the gap, between the associated plates and sintered thereto.

Abstract: An electrochemical cell 10 housing a cylindrical housing 12 and a solid electrolyte separator tube 24 located concentrically therein, dividing the housing into an electrode compartment in the tube and an electrode compartment outside the tube. The cell has a solid electrolyte holder 36, 74 located in the tube and containing active electrode material 54. One of the electrode compartments contains active anode material, the other containing active cathode material. The electrode material in the holder is in electronic contact with the electrode material 54 in the housing outside the tube.

Abstract: The invention provides a method and apparatus for making an electrochemical cell solid electrolyte holder. A layer of solid electrolyte powder or its precursor is formed around an externally screw threaded mandrel. The powder is pressed to form the holder in a green state with internal threads formed by the mandrel. The mandrel is screwed axially out of the green holder, after which the green holder is sintered. In the apparatus there is a mandrel which has external threads, and a flexible sheath. The mandrel is receivable in the sheath to provide an annular space around the mandrel for receiving a powder to be isostatically pressed by the sheath. The space is provided between the sheath and a mold, but can, instead, be provided between the mandrel and sheath, or between two sheaths between the mold and mandrel.

Abstract: A laterally compressed envelope of solid electrolyte material is provided for use as an electrode holder in an electrochemical cell. It has two opposed major faces sealed together along at least part of the periphery of the envelope, each major face being provided by a sheet of said solid electrolyte material. Each sheet is provided on its inner surface with a plurality of ribs or corrugations extending alongside one another, each rib or corrugation of each said sheet crossing over a plurality of the ribs or corrugations of the other said sheet. The envelope has an internal volume, between the sheets, defined at least in part by grooves or valleys between the ribs or crests of the corrugations. Each part of said internal volume is in communication with each other part of said internal volume. The invention also provides a method of making the envelope, and an electrochemical cell in which the envelope forms an electrode holder.

Abstract: The invention provides a method and apparatus for making an electrochemical cell solid electrolyte holder. A layer of solid electrolyte powder or its precursor is formed around an externally screw threaded mandrel. The powder is pressed to form the holder in a green state with internal threads formed by the mandrel. The mandrel is screwed axially out of the green holder, after which the green holder is sintered. In the apparatus there is a mandrel which has external threads, and a flexible sheath. The mandrel is receivable in the sheath to provide an annular space around the mandrel for receiving a powder to be isostatically pressed by the sheath. The space is provided between the sheath and a mould, but can, instead, be provided between the mandrel and sheath, or between two sheaths between the mould and mandrel.

Abstract: The invention provides a solid electrolyte separator for separating two electrodes from each other in an electrochemical cell. The separator is of composite layered construction and comprises at least one porous layer of solid electrolyte material having a plurality of interconnected channels or pores in its interior and opening out of its surface, and a dense layer of non-porous solid electrolyte material. The layers are integrally bonded together, face-to-face, and each porous layer is an outer layer of the separator.

Abstract: The invention provides a high temperature rechargeable electrochemical power storage cell comprising a cell housing defining a cathode compartment containing a cathode and containing an anode structure located within the cathode compartment and comprising a plurality of holders filled with active anode material which is molten at the operating temperature of the cell. The anode structure defines a conduit containing active anode material and the holders are flattened in shape and spaced along the conduit in series from one another. The interior of each holder is in communication with the conduit and each holder has a pair of oppositely outwardly facing major faces extending transversely to the conduit and comprising a material which is a conductor of the active anode material.