Abstract: A sodium/sulphur cell includes a case and a closure member. Each of the case and the closure member is formed of a composite material consisting of a substrate and a deformable metal layer mechanically fixed to the substrate. The substrate is formed of a material which is harder than the deformable metal. An outwardly extending annular flange is formed at the open end of the case. The closure member is secured to the annular flange by a solid phase bond thereby to close the case.

Abstract: An article includes a ceramic member (5) and a composite member (9) bonded together. The composite member is formed of a substrate member and a deformable metal layer which is mechanically fixed to the substrate member. The substrate member is formed of a material which is harder than the deformable metal. The ceramic member and the deformable metal layer of the composite member are hermetically sealed together by a solid phase bond formed by ultrasonic welding.

Abstract: The method of making a gas tight seal to the safety reservoir of a sodium sulphur cell so that an overpressure can be applied to force sodium through a hole in the base of the reservoir to wet the active region around the reservoir. The form of the seal may also provide constructional advantages.

Abstract: It has hitherto been difficult to achieve the even deposition of a cup-shaped body from slurry flowing around a mandrel. This specification discloses a deposition apparatus including control means providing a substantially uniform slurry flow rate over all surfaces of the mandrel to give uniform deposition.

Abstract: A welding electrode arrangement comprising an inner electrode and a plurality of electrically interconnected outer electrodes defining a closed figure about the inner electrode, the outer electrodes being resilient in a direction substantially parallel to the axis of the closed figure, the outer electrodes further being in the form of a plurality of inwardly directed fingers extending from and integral with an outer connecting rim.

Abstract: An alkali metal energy conversion device, particularly a sodium sulphur cell has a cylindrical outer casing (18) containing a tubular solid electrolyte (10) of beta alumina. An outer cathode region between the electrolyte (10) and the casing (18) contains sulphur, and an inner anode region in the electrolyte tube contains sodium. An alpha alumina lid (12) closes the tube (10) and holds a current collector (15). The cathode region is sealed by an annular metal element (23) which is thermocompression bonded about its inner periphery to the lid (12) and is welded about its outer periphery to the casing (18). A second annular metal element (26) is thermocompression bonded to the lid (12) wholly inside the first annular element (23) and is welded to the current collector.The metal elements (23, 26) are bonded to the lid (12) before the lid is glazed to the electrolyte tube (10) and before the first element (23) is welded to the casing (18).

Abstract: In a sodium sulphur cell, improved protection of a cathode current collector is obtained by isostatically pressing graphite foil or flakes onto the surface of the collector, which surface is preferably roughened or coated with an intermediate conductive layer such as a nickel-chromium alloy or a conductive carbide providing a rough surface.

Abstract: In a sodium sulphur cell having, within a metal housing, a ceramic electrolyte tube separating the liquid alkali metal from the cathodic reactant, a current collector extends into the region inside the electrolyte tube and is electrically insulated from the electrolyte by an insulating element. The metal housing is sealed to the insulating element in a region around the current collector which region has a maximum cross-section substantially less than the maximum cross-section of the electrolyte tube and preferably lies wholly within the outer periphery of the electrolyte tube. The small seal areas with the constructions described give improved economy and reliability. The constructon has particular advantages with cells of short length.

Abstract: An arrangement for controlling the charge and/or discharge cycles of an alkali-metal/sulphur cell or battery has detecting means for detecting predetermined high and/or low levels of alkali-metal in the anode compartment of a cell or in an alkali-metal reservoir communicating with the anode compartment whereby the end of the charge and/or discharge cycles is determined. Alternatively, similar detecting means can be associated with an alkali-metal/alkali-metal cycling device which is connected electrically in series with a group of series-connected cells of an alkali-metal/sulphur battery to determine the end of the charge and/or discharge cycles of the battery.

Abstract: A current collecting pole associated with an alkali metal-sulphur cell comprises a first layer of an electronically conducting material which is resistant to the corrosive action of sulphur and alkali metal polysulphides (e.g. carbon or graphite) and which defines a continuous surface in contact with the sulphur and alkali metal polysulphides and a second layer of a higher electronically conducting material which is in electrical contact with the first layer over the surface of the latter remote from the sulphur and alkali metal polysulphides.