Safety characteristics of lithium alloy/metal sulfide batteries

Lithium alloy/iron sulfide batteries have been under development at Argonne National Laboratory and at industrial laboratories worldwide for more than 20 years. Considerable data have been accumulated concerning th safety aspects of this battery system. Current technology employs a two-phase Li alloy negative electrode, a low melting LiCl-rich LiClsingle bondLiBrsingle bondKBr molten salt electrolyte and either an FeS or an upper-plateau (UP) FeS2 positive electrode assembled into an ‘electrolyte-starved’ bipolar cell configuration. Although extensive safety tests on the Li alloy/FeSx battery systems have not been conducted, those that have indicated that these batteries are inherently quite safe. Hundreds of prismatic laboratory and engineering sized cells have been built and tested at Argonne National Laboratory and several industrial firms without safety incidents. These factors lead to the conclusion that it will be unlikely that any elaborate safety features will have to be engineered into Li alloy/FeSx batteries to meet the safety requirements for electric-vehicle applications. More extensive safety tests will be conducted as part of the ongoing development program to validate this conclusion.