Li-ion battery calendar and cycle life degrade at elevated temperatures due to processes involving the interaction of electrolyte salt, solvents and battery electrode materials. The major factor impacting automotive Li-Ion battery pack safety is the use of high vapor pressure and low flashpoint carbonate electrolyte solvents. Development of high voltage cathode materials requires new solvents and salts with electrochemical stability and safety that are beyond what regular state-of-the-art commercialized electrolytes can provide. Leyden proposes development of a new high voltage Liion battery electrolyte combining lithium imide salts with Silatronix advanced organosilicon solvent system. Imide salts such as LiTFSI and LiBETI provide a greater level of thermal stability. Leyden developed a current collector technology that solves the aluminum corrosion issue in imide electrolytes. Silatronix has developed organosilicon compounds which are thermally and electrochemically stable, with a vapor pressure significantly lower than the linear carbonates commonly used in Li-ion battery electrolytes. The proposed program will combine both technologies allowing the use of high voltage cathode materials, increasing battery energy density and extending the operating temperature range of the battery. Commercial Applications and Other Benefits. Success of this program will lead to lower cost and better performing lithium ion batteries for PHEVs and BEVs. Overall system cost will improve due to increased energy density and simplification of thermal management systems. Abuse tolerance of the system will increase as the new electrolytes will have lower vapor pressure and better stability at high temperature.
