Sodium-sulphur batteries for naval applications

Since 1981 the Electrochemistry Group of TNO has carried out a research program for the Royal Netherlands Navy (RNLN) with respect to batteries and fuel cells. Part of this Advanced Batteries program was the evaluation of possible alternatives for the batteries in conventional diesel-electric submarines and ships. From this evaluation the high temperature sodium-sulphur battery proved to be the most promising candidate. To investigate the feasibility of the sodium-sulphur battery for naval application, calculations have been made on the expected performance within the two envisaged applications. To validate the calculation, experimental testing was carried out on the submarine application. During operational missions the application hardly requires any supply of heating energy. Within the submarine application there is no need for installing a cooling system for the battery. Shock and vibration tests on a 10 kWh module did not lead to any measurable decrease in performance. Calculations show that the operational characteristics of a submarine equipped with sodium sulphur batteries outperform a submarine equipped with the traditional lead acid batteries. The short lifetime is the most important limitation in all applications.