| Lithium ion battery with high cycle life,high rated voltage,high energy density and green environmental protection and other outstanding advantages,become the first choice of mine uninterruptible power supply battery.However,there are some safety risks in lithium batteries operating under abnormal conditions such as overvoltage,undervoltage,high temperature and short circuit,and the accurate estimation of battery state of Charge(SOC)is the key technology to ensure the safe and efficient operation of battery pack and the full utilization of energy.Therefore,this paper studies the SOC estimation method of lithium batteries,and designs a mining lithium battery management system that can accurately estimate battery SOC.This paper takes the large capacity lithium iron phosphate battery as the research object,studies the advantages of lithium iron phosphate battery,working principle and performance parameters,and through the constant temperature and humidity test chamber,battery charging and discharging tester and other equipment to study and analyze its rate characteristics,temperature characteristics,cycle characteristics and charging characteristics.In addition,the data obtained from the pulse discharge experiment were combined with Matlab software to identify the parameters of Thevenin and dual-polarization equivalent circuit models commonly used in engineering applications,and Simulink tool was used to model and simulate.Through comparative verification,the dual-polarization model with relatively high accuracy was selected to establish the battery equivalent model.It provides a model basis for battery SOC estimation.For the estimation of battery SOC,on the basis of the traditional extended Kalman filter(EKF),the three factors affecting the actual capacity of the battery,including temperature,discharge rate and aging degree,were considered.The EKF method based on multi-parameter modification was proposed to estimate SOC,and the accuracy and convergence of the estimation were verified through the pulse discharge condition.The results show that even if the initial SOC value is not correct,the proposed method can quickly converge to the correct value and the estimation accuracy is less than 5%,which meets the requirements of SOC estimation accuracy for mining lithium batteries.After completing the battery modeling and SOC estimation,the software and hardware are designed according to the functional requirements of the system.In the system hardware design,according to the overall structure and functional requirements of the system,a scheme based on SH367309 digital front-end chip and STM32F103RCT6 as the main control chip is adopted,and the battery parameter acquisition,power module,charge and discharge management circuit design is completed.In the system software design,based on the hardware circuit,using modular design,the workflow of each function module is explained in detail,and the system battery parameters collection,balance control,data communication and other functions are realized.Aiming at improving the performance of mine power supply,this paper designed and built the performance test platform of mine battery management system.The system is verified by relevant tests.The test results show that the data acquisition accuracy of the system is in line with the safety technical requirements of mining lithium battery,the balance and protection functions can also meet the expected requirements,and the battery pack composed of 8 lithium iron phosphate batteries can be effectively managed and protected.The development of the system has improved the problems of poor consistency,poor performance and low energy utilization of lithium batteries for mining,and has important engineering significance to improve the safety and stability of mine power supply equipment.Figure [63] Table [19] Reference [81]... |
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