Current Trends in the Development of Sodium Sulphur Batteries

The current status of sodium sulphur technology in CSPL is outlined. 350 Wh cells have now been developed with energy densities of 0.36 Wh/cc and 0.16 Wh/g and much of the R & D effort is now being directed towards battery design. Because it must be thermally insulated, the shape of the battery and the thickness of the insulation are significant and it is possible to realise gross battery energy densities of between 0.1 Wh/cc and 0.25 Wh/cc, volumetric energy density normally being the more critical. These are some three times greater than for conventional lead acid batteries, and combined with operating characteristics which differ markedly with conventional batteries, they could offer a number of interesting applications in addition to road transport and load levelling.