Evaluation of electrode coatings using in-line non-destructive techniques and understanding the effect of electrode manufacturing defects on lithium-ion battery (LIB) performance is vital to the quality control process and key to reduce the scrap rate during cell manufacturing. In this regard, it is vital to quantify the effect of various defects that are generated during electrode coating process (Layered NMC532 cathode in this study) on LIB performance. To this end, we demonstrate defect detection and porosity measurement using IR thermography and thickness measurement using a laser technique at high line speeds. We show the comparative effects of different defects that were intentionally generated such as agglomeration, pinholes, and non-uniform coating on LIB performance in full coin cells and large pouch cells. The results show that the electrodes with more coated/non-coated interfaces had greater capacity fade than baseline electrodes at high current densities and that pinholes and agglomerates did not affect the performance adversely. In conclusion, these types of characterization of control samples shows the importance of monitoring and early detection of the electrode defects during the coating process for minimization of cell rejection rates prior to fabrication and formation cycling.

Acknowledgement: This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy).