(Invited) Lithium-Ion Batteries for Fast Charging Application

Abstract

Development of lithium-ion batteries (LIBs) has dramatically boosted market adoption of electric vehicles (EVs). However, further improvement in LIBs is still needed for EV application, such as fast charging. The state-of-the-art chemistries, such as LiNixMnyCo1-x-yO2 (NMC) and graphite, are capable for fast charging. However, the constraints in mass transport limit the electrode thickness and cell energy density. The United States Department of Energy (DOE) has develop a research portfolio with a goal of enabling a 10-minute (6C) recharge time, similar to a typical gasoline engine refueling time while delivering a cell energy density higher than 180 Wh/kg with an energy retention greater than 80% after 500 cycles [1]. When charging a LIB, lithium ions travel from the cathode to the anode via liquid electrolyte, which includes several diffusion steps 1) solid diffusion through active material particles, 2) diffusion across the electrode/electrolyte interface, and 3) through porous electrodes via electrolyte. Each step contributes to the barrier of enabling fast charging [2].In this presentation, the impact of cell components, including anode, cathode, separator, on fast charging will be determined. Some strategies in enhancing the fast charging capability will be discussed. Acknowledgment This research at Oak Ridge National Laboratory (ORNL), managed by UT Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO).