Rechargeable lithium power systems using sulfur dioxide as the electrolyte solvent are prime candidates for the advanced basing system battery. Sulfur dioxide electrolytes have the distinct advantage over allorganic electrolytes of thermodynamic stability towards lithium, albeit their vapor pressure versus solute concentration is more variable.The electrolyte vapor pressure can be bothersome for large batteries designs of several kilowatts and up. This program explores both an engineering and chemical solution to handling the sulfur dioxide electrolyte vapor pressure in large prismatic cells. The engineering approachinvolves stress analysis of cell designs as a function of temperatureand loading followed by physical testing of the most promising design. The chemical approach is to lower the vapor pressure by increasing the solute concentration, then to test the impact of increased solute concentration on cell rate capacities and cycle life using a rechargeable lithium/sulfur dioxide system for test purposes. The program objective is to set design concepts and guide lines
