A fast measuring device for impedance spectrum of lithium-ion battery based on FPGA

Lithium-ion battery quickly developed into a new generation of energy because of its advantages of small selfdischarge, large energy density, good safety and memory-memory effect.Electrochemical impedance spectroscopy (EIS) measurements are widely used in the performance evaluation of lithium-ion batteries. At present, the traditional AC impedance spectrum test instrument uses sweeps, which has disadvantages such as long test time and expensive price. This design uses the field programmable gate array (FPGA) as the controller drive peripheral module. Based on the fast Fourier transform (FFT) measurement method, the upper computer software is developed for data processing and impedance spectrum mapping. The design is mainly divided into FPGA control logic and upper computer software. FPGA control logic adopts modular design. The top level is divided into data analysis module, control module, signal occurrence module, analog to digital conversion module, FIFO cache module and USB communication module to realize superimposed sine signal occurrence, data acquisition and communication with upper computer. The upper computer software design is based on the Visual Studio development environment, developed using C # and Windows Form, realizing the function of data sending and receiving, data processing, and impedance spectrum mapping. This design verified the reproducibility of the system using multiple measurements, yielding the standard deviation of multiple measurements. The accuracy of the system was verified using a comparison with the acquisition card-based measurement device. The results show that this system can be used as a tool to measure the impedance spectrum of lithium-ion batteries.