基于STM32和BQ76940的电池管理系统设计

Design of Battery Management System Based on STM32 and BQ76940

利用STM32单片机设计了一种电池管理系统,实现15节串联锂电池的有效管理。采用BQ76940电池监控芯片设计检测单元,并基于开关电容的电力、电子、电路设计主动均衡单元。系统还利用安时积分法和开路电压法估算电池的荷电状态(State of Charge,SOC),以及利用电池等效模型和通过参数辨识的方法实现在线检测电池的内阻增大性失效故障。介绍了该电池管理系统软硬件的设计方法,并对电池管理系统中的检测单元、均衡单元和内阻辨识进行了测试。实验结果表明:该电池管理系统能够采集电池的电压、电流和温度,能对电压不一致的单体电池进行均衡,并且有效辨识出电池的内阻,具有采样精度高、均衡效果好和能在线检测电池内阻等优点。

A battery management system(BMS)is designed to manage 15 lithium battery cells by using STM32 microcomputer.Firstly,a battery monitoring chip BQ76940 is used to design measurement unit,a switchedcapacitor-based circuit is used to design active equalization unit.Then,the SOC of battery is estimated by the current integration method and open-circuit voltage method,while the internal resistance augmentation failure of battery is detected on-line by battery equivalent model and parameter identification method.The design of both hardware and software of the BMS is introduced in detail.And experimental results for measurement unit,equalization unit and internal resistance identification are provided.The results show that the battery management system can collect the voltage,current and temperature of the battery,balance the single battery with different voltage,and effectively identify the internal resistance of the battery,and it has the advantages of high measurement accuracy,well equalization performance and online detection of the internal resistance for batteries.