Method and device for establishing regression model of electrochemical characteristic impedance of lithium battery

• Main Authors: CHEN BIN, FAN LI, FENG FEI, HE ZHENZHEN, ZHANG KAIQING, YAN WENSEN, WANG PANPAN
• Format: Patent
• Language: Chinese; English
• Published: 04.01.2022
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

The invention relates to a method and device for establishing a regression model of electrochemical characteristic impedance of a lithium battery. The method comprises the steps: obtaining an electrochemical impedance spectrum of a solid-liquid mixed electrolyte lithium battery based on different temperatures and SOC conditions; describing the characteristic impedance of the solid-liquid mixed electrolyte lithium battery electrode process dynamics, and selecting characteristic points from a Nyquist graph obtained after a electrochemical impedance spectroscopy test for analysis, wherein the positions and meanings of the characteristic points are partially changed along with the change of the battery system; and determining a nonlinear relationship between the temperature of the characteristic impedance of the solid-liquid mixed electrolyte lithium battery and the SOC according to the characteristic points to obtain a nonlinear regression model. According to the invention, comprehensive tests are designed, a se