Soh Estimation And DSP Implementation Of Lithium Ion Battery Based On Characteristic Parameters Of IC Curve

Due to the high efficiency and good environmental benefits of electric vehicles,the electric vehicle industry has gained unprecedented development in recent years.The problem of capacity decline caused by battery aging is the key to restrict the development of electric vehicle and battery storage technology.The battery health status(SOH)is a comprehensive evaluation index to evaluate the aging degree of battery.It relate to the capacity of vehicle's mileage and power output.It is one of the difficulties of online estimation of battery management system.The electrochemical in situ analysis is an important method for the analysis of the decline mechanism of lithium ion batteries,which reveals the relationship between the external characteristics of the battery and the internal changes.The main purpose of this paper is to study the implementation of electrochemical in situ analysis in DSP.The main contents and results are as follows:(1)We analyze the principle and aging mechanism of the battery through the battery life cycle experiment.The change rule of internal change and capacity increment curve of lithium-ion battery in aging process by electrochemical in situ method.The relationship between the change of the volume increment curve and the internal aging of the battery studied under different experimental conditions.(2)In order to realize the estimation of battery health state by electrochemical in-situ analysis,the change rule of capacity increment curve and extracted the corresponding voltage values of each peak and peak value as characteristic parameters.Through grey correlation,compare the correlation between characteristic parameters and battery health status,identified the key related parameters as the estimation parameters of subsequent battery health status.(3)By using the estimation model,input the characteristic parameters of the capacity increment curve as the model input and used the battery SOH as the output of the model.The battery aging data a used to train the model,and the influence of different training parameters on the accuracy difference and confidence interval analyzed.Finally,put the model parameters to DSP which trained by battery operation data.(4)The mathematical modeling of the electrochemical in situ analysis is carried out,and the method to be realized in DSP is sought.The hardware experiment platform is designed and built.The open circuit voltage curve of the battery is recorded during the battery constant current charging process.The on-line calculation of the capacity increment curve is realized by using DSP.Comparing the different calculation results of different algorithms and different parameters,compared with the data collected from ARBIN system,and selecting the best method.Finally,according to the design of hardware circuit and functional requirements in the battery constant current charging process using DSP real-time recording battery charging process,calculating the capacity increment curve and extraction capacity increment curve parameter,SOH estimation by using the neural network model after training,to obtain satisfactory results.