Design And Implementation Of Lithium Battery Management System Based On STM32

Lithium batteries are widely used in home appliances,medical,industrial,agricultural and other equipment to replace non-renewable energy sources,and alleviates the problem of energy shortage.At present,there are still many problems to be solved in the development of lithium batteries,Lithium batteries will be damaged under conditions such as overvoltage,undervoltage,and overcurrent,which will lead to a reduction in service life and even more serious explosion and fire safety problems,leading to a device using a lithium battery is damaged.In addition,the estimation accuracy of the state of charge(SOC)of the lithium battery is insufficient,which makes the working efficiency of the lithium battery very low.Therefore,the design of a safe,reliable and stable battery management system(BMS)has great practical significance and practical value.The main research content of this paper is divided into the following parts:(1)This dissertation selects ST’s product STM32F103RBT6 controller as the system’s main control chip,and TI’s product BQ76940 as the front-end data acquisition chip.This dissertation designs the hardware circuit module according to the structure of the BMS,including the main control module,power module,data acquisition circuit,communication module,etc.This dissertation designs the software function flowchart,and write the program in C language in Keil u Vision5 software development environment.(2)For the SOC estimation of lithium batteries,by comparing and analyzing the characteristics of various equivalent models of lithium batteries,This dissertation chooses a second-order RC equivalent circuit model that is closer to the real circuit,and expands the Kalman filter by dynamically modifying the power per unit time.The algorithm performs SOC estimation and data simulation in Matlab / Simulink.Compared with using the extended Kalman filter algorithm(EKF)alone,it has better estimation accuracy.(3)In the Visual Studio 2017 software development environment,This dissertation uses the C# programming language to develop the host computer software,and uses the Alibaba Cloud Internet of Things cloud platform and BMS for data interaction,which greatly facilitates users to check the use status of lithium batteries.(4)This dissertation sets up a complete BMS.By simulating the overcharge,overdischarge and other working conditions of the lithium battery,it is verified that the BMS designed in this dissertation can reliably guarantee the safe use of the lithium battery and achieves the expectative results of the experiment.