Design of Automatic Measurement System of Lithium Battery Electrochemical Impedance Spectroscopy Based on Microcomputer

A system of miniaturized lithium battery electrochemical impedance spectroscopy (EIS) measurement is designed with high precision impedance converter chip AD5933 as its core. The measurement range of the system is from 0.010Hz to 100 KHz. Meanwhile, by using a high-level programming language of C#, an interface is developed which can real-time graphic display of EIS information. Through measurement and analysis of two types of impedance, the results show that detection precision of the system is less than 3.5%. Finally, amplitude-frequency response curves and Nyquist plots of HL-18650 M lithium battery at different state of charge (SOC) levels are measured. Compared with lithium battery EIS measurement system by traditional division, this system has the outstanding advantages of small size, high level of integration, low cost, simple operation and high precision. It is helpful to the mass production and application of lithium battery EIS measurement system.