Wednesday, 4 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
Lithium-ion batteries (LIBs) are the energy storage system of choice for high energy and power applications, such as electric vehicles. However, LIBs still face multiple challenges, especially during operation under extreme, such as low-temperature and fast charge. Under such conditions, lithium plating may happen, which can deplete the cell capacity, diminish cycle life and may lead to safety incidents. For example, if dendrites are formed, instead of a film-like lithium metal deposition, short circuit and thermal excursion may ensue. Graphite anodes are susceptible to lithium plating due to the proximity of their potential to the reversible potential of lithium. In a typical Li-ion cell, if the graphite anode potential is driven below 0.0 V vs. Li/Li+ during cycling, deposition of lithium may occur. In the present study, an anode control based charging scenario is proposed. Fast charging is conducted by imposing a constant current – constant voltage (CCCV) protocol in the negative electrode with an arbitrary lower cutoff potential (> 0.0 V vs Li/Li+). During the anode controlled charging, both the cathode potential and the full cell voltage are also monitored. Electrochemical analysis based on the anode control strategy and the effect on lithium plating and cell performance will be presented.