基于单片机和压电晶片的电池管理系统设计

Design of battery management system based on microchips and piezoelectric wafers

锂电池荷电状态估算（SoC）以及均衡管理是电池管理系统的热点和难点。鉴于磷酸铁锂软包电池在SoC为10%~90%范围内电池开路电压变化很小,对传统的基于开路电压估算荷电状态方法就要求很高的测量精度。设计了一款分布式电池管理系统,对电池电压、温度、电流等进行监控。并采用两个压电陶瓷晶片估算荷电状态（不需要与电池包进行电气连接,减小了对电池包寿命的影响）,产生的特定信号穿过电池包后发生变化,依据检测到的信号幅值与SoC之间的关系和开路电压进行SoC估算。实验结果表明,设计的电池管理系统对电池包参数采集满足精度要求,并验证了压电效应估算SoC方法的可行性。

State of charge（SoC）estimation of the electric vehicle（EV）and equalization management are the research focuses of battery management system（BMS）.However,as the voltage of Lithium iron phosphate battery varies a little while SoC ranges from 10%to 90%,traditional SoC estimation methods need more precise measuring accuracy which use charge bookkeeping and cell voltage measurement.A distributed BMS is designed to monitor battery＇s voltage,current and temperature.Besides,a couple of piezoelectric wafer are used to estimate SoC（where BMS has no electrical connections with battery pack and the influence on battery pack＇s life is shorten）,where the special signal sent by transmission circuit changes after going through the battery.Signal＇s amplitude and open-circuit voltage are used to estimate SoC.Experiment result shows that the measuring accuracy of BMS meets the demand and verified the feasibility of using piezoelectric effect to estimate SoC.