Monitoring Lithiation Dynamics in Commercial Lithium-Ion Batteries

摘要

Commercial lithium-ion batteries (LIBs) are conventionally managed using a combination of external measurements that include voltage, current flow and temperature. Developments in the use of fiber-optic evanescent wave sensors within LIBs provide a potential alternative method to monitoring the transport of lithium ions during battery operation. We present a method to model the interaction between fiber-optic evanescent wave sensors and LIBs to demonstrate the significant factors affecting the signal, which include the electrode capacity, charging rate, particle size, and diffusion coefficient. As the concentration of lithium-ions at the surface of graphite electrodes (anode) varies, the transmittance through the sensor changes both, during operation and during rest periods. Hence, relevant information on the operation of the battery cell is acquired even as electrodes undergo relaxation. Monitoring lithium-ion surface concentration during lithiation in commercial b atteries will therefore allow for more accurate and safer operation and at the same time, will provide an alternative method to estimating LIBs state of charge and state of health.