Research On Modeling And SOC Estimation Of Aluminum-air Battery

With the rapid development of the times,environmental issues and energy issues have become one of the most concerned issues in the world.As a new generation of new energy battery,Aluminum-air battery has the advantages of high power density,high specific energy,rich raw materials,long life and low cost.It has been demonstrated to be applied in the fields of backup power for communication base stations,power supply for electric vehicles and driving energy for underwater facilities.At present,the lithium-ion battery monitoring system with relatively mature technology has appeared on the market.If it is simply transplanted to the aluminum-air battery,monitoring Battery Operation Status,there will be problems of battery mismatch and inaccurate test results.Nowadays,the aluminum-air battery monitoring system has some problems,such as modeling and State of Charge(SOC)estimation.At present,there is not a set of mature monitoring system to monitor the running state of aluminum-air battery.In view of the above shortcomings,this paper designs a set of aluminum-air battery monitoring system.The equivalent model establishment and SOC estimation of aluminum-air battery are mainly studied.Therefore,it is necessary to design an energy management system for aluminum-air battery.Firstly,the working principle and discharge characteristics of aluminum-air battery are studied and analyzed.The experimental results show that the aluminum-air battery can not only sustain long-term discharge,but also has high specific energy,which can meet the demand of standby power supply for communication base station.A relatively accurate equivalent circuit model of the two order RC aluminum-air battery is established.The curves between open circuit voltage(OCV)and state of charge were calibrated by discharge experiments at different discharge rates.At the same time,the recursive least squares method with forgetting factor is used to identify the parameters online.Finally,the accuracy of the battery model is simulated on Matlab/Simulink.Because the open-circuit voltage method can not measure SOC in real time,the time integration method has some problems such as inaccurate initial SOC value and accumulated error.The real-time variation of the open circuit voltage of the battery can be obtained by real-time identification of the second-order RC equivalent circuit model of the battery.Based on this,a piecewise SOC estimation method combining open circuit voltage method with time integration method is proposed.The simulation results show that the proposed method not only overcomes the disadvantages of the ampere-time integration method and the open-circuit voltage method,but also has high accuracy.Finally,a set of monitoring system for aluminum-air battery is designed by modular system design.It includes hardware design,software design and test platform design.The test platform verifies that the system not only has complete functions and high precision of data acquisition,but also significantly improves the accuracy of battery modeling and SOC estimation.