The development of aluminum aqueous batteries for torpedo propulsion: prototype development of a replenishment electrolyte management system for activation and control of a pile configured battery cartridge

Development of electric propulsion systems for torpedo applications imposes significant challenges with regards to system energy and power densities, both gravimetric and volumetric. Energy and power goals of 200 Wh/kg and 1200 W/kg, respectively, for the overall battery system have necessitated the development of recirculating aqueous electrolyte systems capable of run-time optimized molar concentrations of both the products and the reactants. Several electrolyte operating concepts have been evaluated, ranging from closed system (no active control of the electrolyte concentration) to delayed and variable rate controlled injection of both solute (NaOH) and solution (sea water and NaOH solution). The development of an intelligent electrolyte management concept, utilizing a replenishment electrolyte management system results in projected improvements in energy density of an Al-AgO battery, for a particular torpedo application, from 100 Wh/kg to 200 Wh/kg, enabling the Al-AgO battery system to meet the torpedo propulsion performance requirements, which otherwise could not be met with other primary or secondary battery systems.