基于状态与模型参数联合估计的老化电池可充入电量估计方法

An Estimation Method of Rechargeable Electric Quantity for Aging Battery Based on Joint Estimation of State and Model Parameters

在电力系统中,电池储能得到了广泛的应用,为了保证电池储能系统的运行效果,有必要对电池状态进行准确估计,电池实际可以充入的电量在一定程度上决定了电池的能量存储能力,然而仅通过电池电压、电流和温度等外部特性参数难以准确体现电池实际可充入电量状态,尤其在电池健康状态衰退的不同阶段其可充入电量估计问题一直以来都难以得到有效解决。因此,该文以Thevenin等效电路模型为基础,提出了电池可充入电量的概念,构建了可充入电量与电池开路电压(OCV)的对应关系曲线,分析了电池老化后直流内阻变化对电池可充入电量的影响,提出了基于双自适应双扩展卡尔曼滤波(ADEKF)的电池状态和模型参数联合估计方法,实现了任意老化状态电池的可充入电量在线估计。以3节不同老化程度的三元锂电池为研究对象,在联邦城市运行工况(FUDS)下验证电池状态和模型参数估计结果,在0.5C倍率恒流充电工况下验证可充入电量损失的估计结果。实验结果表明,对于新电池,FUDS工况下可充入电量估计误差小于1%,对于实验用老化电池,最大可充入电量估计误差为2.7%。通过3节不同老化程度电池在恒流0.5C倍率恒流充电下的状态估计结果比较,进一步验证了所提方法对可充入电量估计的有效性。

Battery energy storage system has been widely used in power systems.In order to ensure the operation effect of the battery energy storage system,it is important to accurately estimate the battery state.The rechargeable electric quantity of the battery determines the ability of energy storage to a certain extent.However,it is difficult to accurately reflect the actual rechargeable electric quantity of the battery only using external characteristic parameters,such as voltage,current and temperature.The problem of the rechargeable electric quantity estimation of batteries in different health states has been difficult to solve,especially in different aging states.In this paper,the concept of rechargeable electric quantity is proposed,the relationship between the rechargeable electric quantity and the open circuit voltage(OCV)is constructed,and the rechargeable electric quantity affected by DC internal resistance is analyzed based on the Thevenin equivalent circuit model.Besides,a joint estimation method of battery states and model parameters is proposed based on dual adaptive dual extended Kalman filter(ADEKF),which realizes the rechargeable electric quantity estimation of the battery in any aging state.Taking three batteries with different aging states as the research object,the battery state and model parameter estimation results are verified in the federal urban driving schedule(FUDS)operating condition,and the estimation results of the rechargeable electric quantity loss are verified at 0.5C constant current charging.The experimental results show that for the new cell,the estimation error of the rechargeable electric quantity is less than 1%,and the error affected by DC internal resistance is 0.031A·h.For the aged cell,the estimation error of the rechargeable electric quantity is 2.7%,and the error affected by DC internal resistance is 0.074A·h.The comparison of the state estimation of three batteries with different aging states at 0.5C constant current charging condition further verifies the effectiveness of the proposed method for electric quantity estimation.