Quantifying the Effect of Lithium-Ion Electrode Manufacturing Defects on Electrochemical Performance

Abstract

Understanding the effect of electrode manufacturing defects on lithium-ion battery (LIB) performance is key to reduce the scrap rate. 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. Previously, we have shown the comparative effects of different defect types such as agglomeration, pinholes, metal particle contamination and non-uniform coating on LIB performance in full coin cells.1 In this study, we have quantified the effect of these defects in 1.5 Ah pouch cells in order to investigate the effect in pilot-scale LIB format(s). The results showed that the electrodes with more coated/non coated interfaces had faster capacity fade than baseline electrodes at high current densities. Pouch cells with electrode agglomerates and pinholes were also fabricated and a comparative study was performed. In order to further validate our latest experimental findings, we have adopted mathematical simulation methods to explore the effects of microstructural inhomogeneities on cell electrochemistry. The conclusions from this study provide the importance of monitoring and early detection of the electrode defects during the coating process to minimize cell rejection rates prior to fabrication and formation cycling.