面向不同电流工况的锂离子电池改进EECM研究  

Improved EECM for lithium-ion batteries under different current conditions

作　　者：张志行 韩雪冰[1] 冯旭宁[1] 卢兰光[1] 王贺武[1] 欧阳明高[1] ZHANG Zhihang;HAN Xuebing;FENG Xuning;LU Languang;WANG Hewu;OUYANG Minggao(School of Vehicle and Mobility,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学车辆与运载学院,北京100084

出　　处：《电力工程技术》2023年第4期2-12,共11页Electric Power Engineering Technology

基　　金：国家自然科学基金资助项目(52177217,52037006);北京市自然科学基金资助项目(3212031)。

摘　　要：锂离子电池是新能源汽车动力系统的核心,基于模型的电池管理系统(battery management system,BMS)是保证电池性能充分发挥的关键。然而现有BMS主要采用等效电路模型(equivalent circuit model,ECM),尚未考虑放电倍率对可用容量的影响机制,导致模型在不同放电倍率下以及低荷电状态(state of charge,SOC)区域会存在明显的端电压仿真误差,影响算法精度;尤其是BMS无法准确估计电池放电截止条件,剩余放电电量(remaining discharge capacity,RDC)估计误差大,可能导致电池电压骤降甚至整车抛锚等严重后果。针对以上问题,文中以考虑内部扩散机制的扩展等效电路模型(extended equivalent circuit model,EECM)为基础,对不同倍率的放电电压容量增量(incremental capacity,IC)曲线进行对比分析,利用能斯特方程构造不同放电倍率下的容量-开路电压曲线,提出改进的EECM。所提改进EECM在不同电流倍率和动态工况下的端电压仿真误差均小于传统ECM和EECM,可以提高RDC估计的准确性,有应用于实际BMS的潜力。Li-ion batteries are at the core of new energy vehicle powertrains.The model-based battery management system(BMS)is the key to ensure the full play of battery performance.However,the existing BMS mainly adopts the equivalent circuit model(ECM),without considering the impact of discharge rate on available capacity.Therefore,the model will have significant terminal voltage simulation errors in different discharge rates and low state of charge(SOC)regions,which affects the accuracy of BMS.BMS cannot accurately estimate the battery discharge cut-off condition,and the estimation error of residual discharge capacity(RDC)is large,which may lead to serious consequences such as battery voltage sag and vehicle breakdown.To solve the above problems,based on the extended equivalent circuit model(EECM)considering the internal diffusion mechanism,the incremental capacity(IC)curves of discharge voltage at different rates are compared and analyzed.Nernst equation is used to construct capacity open circuit voltage curves at different discharge rates,and an improved EECM is proposed.The simulation errors of the improved EECM for terminal voltage under different current rates and dynamic conditions are smaller than traditional ECM and EECM.Improved EECM can improve the accuracy of RDC estimation and have the potential to be applied in practical BMS.

关 键 词：锂离子电池 等效电路模型(ECM) 电池管理系统(BMS) 电动汽车 剩余放电电量(RDC)估计 改进的扩展等效电路模型(EECM) 

分 类 号：TM912[电气工程—电力电子与电力传动]