Design Of SOC And SOH Online Estimation System For Vehicle Battery

The lead-acid battery on the traditional fuel vehicle has the characteristic of large starting current as the starting power supply of the vehicle,and the vehicle-mounted lead-acid battery ensures the power supply to the electric system of the whole vehicle,thus being safe,stable and reliable.As the traditional fuel vehicle cannot replace the battery for a short time,the real-time online monitoring of the state of charge of the vehicle-mounted battery can ensure that the battery cannot be overcharged or overdischarged,and the online estimation of the state of health of the vehicle-mounted battery can remind the replacement of the new battery and ensure the driving safety.In this paper,the voltage,current,temperature and internal resistance of the battery will be collected to estimate the SOC and SOH of the battery.The estimated values will be sent online to the vehicle terminal and wireless monitoring terminal through CAN bus communication and NB-IOT wireless communication respectively.The main work is as follows:Literature research on SOC and SOH estimation algorithm of current battery research is carried out,the equivalent circuit model of current battery is introduced,and Thevenin model required by this paper is established through actual testing of battery.Based on the established model and battery test,the extended Kalman filter algorithm is proposed to estimate the SOC of the battery online,and the simulink model is built to verify the results.For SOH estimation of battery,this paper respectively verifies a method based on LIBSVM algorithm to estimate SOH through internal resistance value and voltage value,and another innovative method combining with regression CNN to obtain online estimation of SOH value.On the basis of the above technology,an embedded system platform controlled by an automobile-grade single chip microcomputer is built,and battery parameter acquisition circuit,AC small signal on-line internal resistance measurement circuit,CAN communication circuit and NB-IOT wireless communication circuit are designed.On the built hardware platform,the storage battery parameter acquisition program,SOC and SOH estimation program,CAN communication and NB-IOT communication program and the operation flow and structure of each program are proposed.Build a test platform through PCAN to realize CAN data communication of the platform,configure NB-IOT equipment to access the cloud platform,and conduct on-line test and data acquisition verification on the storage battery.According to the SOC and SOH estimation algorithms proposed in this paper embedded in the hardware platform,the results prove the feasibility and effectiveness of the algorithm.The system designed in this paper has the characteristics of intelligence,accurate data quantity and timely feedback.The added NB-IOT technology can be used for remote feedback processing,which is of great significance to strengthen the protection of the battery,improve the stability of power supply,and ensure the working efficiency and service life of the battery.