Analysis of Spectrum and Discharging Behavior of Lithium-ion Battery Using Equivalent Circuit Model

• Main Authors: Meng-Ting Chang, 張孟婷
• Other Authors: Kuo-Ching Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/51394267058925332726

碩士 === 國立臺灣大學 === 應用力學研究所 === 102 === Many studies of lithium-ion battery (LIB) has been carried out because of the wide use of it. Cost reduction, performance improvement, increase of power, excellent cycle life along with high safety are the main targets of those studies. During the process of LIBs research, it is important to inspect the inner condition of LIBs by making battery examinations. Electrochemical Impedance Spectroscopy (EIS) is one of the commonly used examinations, which is a nondestructive testing and famous for its rapidity. In this thesis, the EIS measurement was performed to obtain the spectra of LIBs. In addition, we simulated the spectra through the equivalent circuit model (ECM) of LIBs. In order to simulate the spectra precisely, we established a simulation method based on electrochemistry and mathematics. Besides, the parameters of the ECM, which were obtained from the simulation results, were analyzed and studied for understanding the effects on the impedance of LIBs caused by different experimental settings. Furthermore, one of the parameters in the ECM helped us gain an important electrochemical parameter--the diffusion coefficient of lithium-ion, which was critical for establishing electrochemical model of LIBs. The equivalent circuit model of LIBs could be further used to simulate the discharging behavior of LIBs. We also provided a method for estimating open-circuit voltage (OCV) of LIBs. This method could successfully predict the OCV of LIBs and thus decrease the time consumed during OCV measurement.