Online Fast Battery Impedance Measurement Method

Battery’s impedance spectrum is one of the most important parameters of an electrochemical cell,and it is one of the parameters indicating the performance of the battery.More mature measurement schemes for battery impedance spectrum are mostly offline measurements.If the battery’s impedance spectrum can be monitored online in real time,then the battery can be monitored and protected for voltage,estimating the state of charge and the state of health of the battery,and at the same time detect hidden points of failure in the battery system.This paper explores and studies the design of the online fast battery impedance measurement method in depth.This paper bases on the current research status and existing problems in lithium-ion battery and battery management systems,and taking quickly and accurately measure the impedance spectrum of the battery as the research focus to design an effective online measurement of battery impedance spectrum.Firstly,through the detailed analysis of the scheme theory proposed in the paper,Focusing on the three key steps of small signal disturbance injection,cross-correlation noise filtering and three-point measurement battery impedance spectrum algorithm,to design the software and hardware about the scheme of on-line measuring battery impedance spectrum.Dsp can not only meet the need of arithmetic operation,but also has the characteristics of flexibility,low price and simple peripheral circuit in digital control.Therefore,the paper uses DSP as the control chip.In this paper,the loop control,the design of PID compensator and the implementation of the algorithm are analyzed and discussed in detail.In the introduction of hardware design,this paper expounds how to realize the operation of de-DC sampling signal by hardware,so as to meet the demand of sampling precision.Finally,the paper builds the software experiment platform on PISM,and compares the experimental data with the data calculated by the formula.The impedance spectrum of the battery is measured by the on-line rapid measurement of the impedance spectrum of the battery.The experimental data are compared with that of the off-line measurement of the impedance spectrum of the battery.The experimental results prove the rationality and feasibility of the scheme proposed in this paper.