Analysis of concentration polarization and discharge characteristics of lithium ion battery
1. School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China； 2. Automotive Engineering Research Institute, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract：To investigate the concentration polarization of lithiumion battery and the influence factors, the typical NCM/C lithiumion battery was tested to obtain the key performance parameters. The electrochemical model was established by COMSOL, and the model was verified by tests. Based on the model, the solid and liquid phase concentration polarization characteristics during discharge and the main factors affecting battery discharge performance were studied. The results show that the effect of changing the particle size of negative electrode on the negative solidphase concentration polarization is more obvious during the discharge process, and the change of the solidphase concentration is about 136.05% of that caused by the positive electrode in the same ratio range. Changing the thickness of the positive electrode is more likely to aggravate the concentration polarization of liquid phase, and the change of the liquidphase concentration is about 199.01% of that caused by the negative electrode in the same amount range. The thickness of positive electrode has significant effect on voltage platform and battery capacity, and the particle size of the negative electrode affects the voltage platform and has almost no effect on the capacity. Comparing the two factors, the positive electrode thickness is the key factor for affecting the concentration polarization and discharge performance of battery.
