No overcharging here.
Lithium-ion batteries are a widely adopted power source for electric vehicles (EV). While having many advantages, the issue of safety continues to plague this technology, particularly of the battery's inherent flammability, which can be exacerbated by overcharging during use.
Methods for overcharge protection have been sought for decades, using cell chemistry instead of electronics. The goal has been to develop a substance that dissolves in the electrolyte of a Li-ion cell, remains inert during normal operation, becomes activated as overcharging begins and curtails the overcharging process by removing excess charges as they arrive at the cathode. Efforts at devising such a material that satisfies the requirements for use in practical Li-ion battery cells designed to power electric vehicles have met with limited success, until Argonne National Laboratory's breakthrough in synthesizing [sub.1,3]-di-tert-[butyl-.sub.1,4]-bis(methoxyethoxy)benzene--ANL-RS2.
Thorough testing by A123 Systems LLC has shown that ANL-RS2 Advanced Redox Shuttle Additive is a highly reliable and high-performance electrolyte additive for EV battery cells using LiFeP[O.sub.4] as the cathode material. When dissolved in the electrolyte of a LiFeP[O.sub.4]-based Li-ion battery cell, ANL-RS2 remains inert until the potential of the cell increases from 3.6 to 3.9 V during an overcharging event. At that point, ANL-RS2 becomes activated and is able to accept excess charges from the cathode and transport them to the anode, thereby accomplishing efficient overcharge protection by providing an internal electrical path for the excess charges arriving at the cathode.
* Argonne National Laboratory, www.anl.gov
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|Title Annotation:||Energy Technologies|
|Publication:||R & D|
|Article Type:||Brief article|
|Date:||Oct 1, 2014|
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