Abstract: A cathode structure for a sodium sulphur cell is formed of a stack of elements of carbon fibre material or predominantly of carbon fibre material, each element being punched out of a sheet of the material having fibres randomly oriented in planes parallel to the plane of the sheet. For a cylindrical cell, the elements are of annular form with a central aperture.

Abstract: In an electrochemical cell, such as a sodium-sulphur cell, having a tube of solid electrolyte material separating a liquid alkali metal from a cathodic reactant, the electrolyte tube is surrounded by constraining means which apply an inward pressure as the cell temperature rises. This is achieved either by having a suitable means, e.g., wire, around the tube with a lower coefficient of expansion than the tube, or by putting powder or particles or corrugated metal or other constraining means between the tube and a surrounding housing, the materials being chosen to have appropriate coefficients of expansion to give the required inward pressure.