VRLA battery state-of-charge estimation in telecommunication powersystems

This paper presents the logical analysis of valve-regulated lead-acid battery discharge behavior and suggests a model for obtaining estimates of the state of charge (SOC) and reserve time throughout discharge. The basis of the model is the relationship between the discharge voltage and SOC. This relationship is valid for a wide range of discharge rates and ambient temperatures as related to the telecommunications backup power supply application. Due to the robust nature of this relationship, only a single discharge characteristic under nominal operating conditions is required by the model. Case studies reveal that the model enables accuracy in estimation of SOC of better than 10% of actual SOC after discharging 10% of the rated capacity. As the discharge proceeds, the error reduces substantially. A feature of the model is that it is easily adaptable to changes in battery characteristics which occur as a result of extreme stress     

阀控密封铅蓄电池的开路电压变化规律

起动型铅蓄电池的开路电压跟荷电态之间存在线性关系,因而可以根据开路电压来推断电池的放电容量或荷电态。阀控密封铅蓄电池的开路电压跟电极表面附近液层中的电解液的密度有关,但它的放电容量不仅跟电池中参与电极反应的电解液的量以及活性物质的量有关,而且还深受反应粒子的扩散过程迟缓性的影响。因而不能直接用开路电压来推断阀控密封铅蓄电池的放电容量或荷电态。     

Battery Management System Based on Battery Nonlinear Dynamics Modeling

This paper presents a method of determining electromotive force and battery internal resistance as time functions, which are depicted as functions of state of charge (SOC) because . The model is based on battery discharge and charge characteristics under different constant currents that are tested by a laboratory experiment. This paper further presents the method of determining the battery SOC according to a battery modeling result. The influence of temperature on battery performance is analyzed according to laboratory-tested data, and the theoretical background for calculating the SOC is obtained. The algorithm of battery SOC indication is depicted in detail. The algorithm of the battery SOC ldquoonlinerdquo indication considering the influence of temperature can be easily used in practice by a microprocessor. An NiMH battery is used in this paper to depict the modeling method. In fact, the method can also be used for different types of contemporary batteries, as well as Li-ion batteries, if the required test data are available.     

Prediction of Battery Behavior Subject to High-Rate Partial State of Charge

An online optimization procedure provides the parameters of a nonlinear battery model by taking into account a few minutes of measured current–voltage data. Within a defined range in terms of charge current, state of charge (SOC), and duration of charge and discharge events, the model is able to capture the relevant battery dynamics and predict the behavior for the next few minutes. From the battery behavior during specific events, the state of the battery can be revealed, which is defined as the state of function. Validation, which is carried out on measured current–voltage profiles, shows the accuracy of prediction during the high-rate partial SOC operation. Even with the data measured during a city drive within a microhybrid electrical vehicle, the method is able to predict the voltage level during high-rate discharge pulses (cranking).      

密封铅蓄电池阻抗参数与荷电态

蓄电池的交流阻抗特性远比理想的单电极要复杂，不同类型的蓄电池的阻抗参数差别很大，其中有些参数有可能用于指示蓄电池的荷电态。密封铅蓄电池的荷电态在50%以上时，电池内阻几乎没有变化，但其电化学反应内阻与双层电容之积，却对荷电态很敏感。     

VRLA蓄电池在线监测技术综述

随着铅酸蓄电池的广泛应用,人们对其运行的安全性、可靠性提出了更高的要求。同时,蓄电池在线监测技术也得到了迅猛发展。文章简单介绍了阀控式铅酸（VRLA）蓄电池在线监测及剩余容量（SOC）在线预测的几种方法,并进行了对比分析,提出了较为有效的监测方法。     

配电终端VRLA蓄电池健康状态评价方法研究与实现

阀控式铅酸蓄电池是配电自动化系统的关键组件之一,作者开展了VRLA蓄电池健康状态评价方法的研究。通过研究VRLA蓄电池放电曲线的特性,得出了蓄电池容量与电压变化率间的关系,并结合蓄电池内阻与现场环境温度对容量的影响,提出了一种基于VRLA蓄电池短时恒流放电曲线的蓄电池健康状态评价方法。同时,设计了蓄电池测试仪,可以在5分钟内完成蓄电池健康评价。通过实验测试验证了所提蓄电池健康状态评价方法的可行性与有效性。     

浅析基站开关电源电池保护方式对蓄电池的影响

文中对基站蓄电池容量衰减过快、使用寿命较短的原因进行了分析，并根据蓄电池的放电特性。对现有基站开关电源的电池放电保护方式存在的不足进行了探讨，提出了将电压保护方式和时间保护方式相结合，同时应用于开关电源的蓄电池放电管理功能中，从根本上解决了避免基站蓄电池的深度放电的问题．延长了蓄电池的使用寿命。     

串联锂离子电池组荷电状态评估方法对比

分析了多芯串联锂离子电池组中各组成电芯初始荷电状态差异引起的安全问题,研究了充电电压、放电电压和开路电压与荷电状态对应关系,并进行了试验验证,定量分析和试验验证了电芯间的初始开路电压差异、初始放电电压差异、初始荷电状态差异三者与锂离子电池组安全性的对应关系,提出了初始荷电状态差异的考核方法。     

阀控式铅酸蓄电池VRLA在线维护技术的应用研究

以往对阀控式铅酸蓄电池的监测仅仅停留在对电池电压和内阻的测试上,没有有效的分析及维护手段,文章从浮充电压对阀控电池容量及寿命的影响角度,讨论了阀控电池浮充状态的分析判断方法,并提出了通过在线充放电的控制来调整阀控电池浮充状态的技术,达到对电池在线维护、改善性能、延长寿命的目的。文中还提出了具体的实现方案,列举了应用实例。     

动力型锂电池SOC与SOH协同估计

锂电池及其应用近年来逐渐成为研究热点。以提高电池管理系统(BMS)对电池荷电状态(SOC)和健康状态(SOH)的估算精确度为目标,在建立二阶Thevenin等效电路模型基础上提出一种能在线协同估算电池荷电状态和健康状态的改进扩展卡尔曼滤波算法。通过分阶段脉冲放电实验,并利用最小二乘法求得模型参数。在动态应力测试工况(DST)下借助Matlab对比分析了改进扩展卡尔曼算法在SOC和SOH估计精确度、错误初值时算法收敛性、算法复杂度等方面的性能。实验表明,利用该算法可以精确估计出各采样点处的SOC和SOH,误差低于1%;且在初值不准确情况下,运行算法可快速收敛至真值附近,算法估算结果的准确性与模型参数的微调无关,鲁棒性较好。     

A new approach to intermittent charging of valve-regulated lead-acid batteries in standby applications

For many years, intensive research has been undertaken to increase the life of valve-regulated lead-acid (VRLA) batteries. Overcharging results in excessive temperature in the battery, which degrades the chemical composition of the electrolyte. When the battery reaches the end-of-charge state, the energy being supplied to the battery is no longer consumed in the charge reaction and this additional energy is dissipated as heat within the battery. At this point, the oxygen cycle accelerates, which leads to temperature rise inside the battery. State-of-the-art control technology is required to control the charging of the battery and prevent the battery going into thermal runaway. This paper discusses the charging strategies for VRLA batteries in standby applications. Intermittent charging decreases the continuous overcharge which arises in the case of float charging. The charging regime used in intermittent charging must ensure the full recharge of the battery. This paper describes a new efficient method of charging batteries employing an intermittent charging technique called "Interrupted Charge Control." Laboratory tests and results are presented.     

通信用密封铅蓄电池组在线诊断技术

通信电源系统中的阀控密封铅蓄电池组是长期处于浮充状态之下工作的。由于它是渐变失效产品，所以蓄电池组中各块电池的浮充电压高低和均匀性以及浮充电流的大小和变化趋势，可以为在线评估蓄电池组的健康状况提供重要的信息。统计结果表明，一旦出现浮充电压的均匀性开始变差和浮充电流持续增大，则蓄电池组的使用寿命只剩下约1／3了。     

锂离子电池高G值冲击安全测试技术

针对锂离子电池带来的安全问题,讨论了锂离子电池的工作原理、充放电特性.结合某型号便携设备用锂离子电池分析了高G值冲击过程对电池的损害,研究了锂离子电池高G值冲击的安全测试技术.     

基于模糊逻辑的变电站蓄电池在线健康状态评估

为了保证变电站直流电源设备运行的安全可靠性,提高铅酸蓄电池健康状态(State of Health,SOH)的评估能力至关重要。提出了一种基于模糊逻辑预测SOH的在线检测法,利用蓄电池在充放电状态下电荷量与开路电压之间的线性关系分别在线、离线检测蓄电池的SOH。实验结果表明,传统的离线法与在线法评估的结果一致,误差均接近2%左右。与SOC在线检测方法相比,SOH对蓄电池健康评估具有灵敏度高、收敛快等特点。     

基于SOC估算的锂电池组复合型均衡拓扑设计

锂电池的均衡管理可以提高锂电池的使用寿命和续航里程。针对磷酸铁锂电池串联电池组中,电池组中各个单体电池之间存在电量不一致的问题,提出一种复合式均衡拓扑结构,通过对单体电池之间的电感或电池组间的变压器选择性放电均衡,实现电池组内的各个单体电池的电量均衡,并测量实际的锂电池放电曲线,拟合锂电池开路电压与SOC的曲线。此外,建立了对应的磷酸铁锂电池Simulink模型,使用SOC估算值作为判断均衡的条件,以提高启动或停止均衡子电路的准确性。在Matlab/Simulink的软件仿真下证明,所提出的复合式均衡方案均衡效果良好,易于实现,控制简易。     

State-of-Charge Determination From EMF Voltage Estimation: Using Impedance, Terminal Voltage, and Current for Lead-Acid and Lithium-Ion Batteries

State-of-charge (SOC) determination is an increasingly important issue in battery technology. In addition to the immediate display of the remaining battery capacity to the user, precise knowledge of SOC exerts additional control over the charging/discharging process, which can be employed to increase battery life. This reduces the risk of overvoltage and gassing, which degrade the chemical composition of the electrolyte and plates. The proposed model in this paper determines the SOC by incorporating the changes occurring due to terminal voltage, current load, and internal resistance, which mitigate the disadvantages of using impedance only. Electromotive force (EMF) voltage is predicted while the battery is under load conditions; from the estimated EMF voltage, the SOC is then determined. The method divides the battery voltage curve into two regions: 1) the linear region for full to partial SOC and 2) the hyperbolic region from partial to low SOC. Algorithms are developed to correspond to the different characteristic changes occurring within each region. In the hyperbolic region, the rate of change in impedance and terminal voltage is greater than that in the linear region. The magnitude of current discharge causes varying rates of change to the terminal voltage and impedance. Experimental tests and results are presented to validate the new models.     

一种电动车用锂电池剩余容量检测系统

针对电动车应用中的需求,提出了一种电动车用锂电池剩余容量(SOC)检测的方法,并设计了一套SOC检测系统。该系统以AVR单片机为控制及计算核心、以ACS712为电流采集器,采用线性光耦隔离模拟电压信号,集合充放电电流对时间的积分和BP神经网络估算两种方法来测量电池SOC值。该系统具有成本低、安全可靠、计算准确等特点,适合在电动车上推广使用。     

A new online state-of-charge estimation and monitoring system for sealed lead-acid batteries in Telecommunication power supplies

This paper presents a new, online, battery state-of-charge estimation and monitoring system for both the discharge and charge periods of sealed lead-acid batteries, commonly used in telecommunication power systems as backup power supplies. The proposed monitoring system is based on discharge time versus discharge rate data given in manufacturers' data sheets, and coulometric measurements, without the need for any battery voltage measurement under open-circuit conditions. The corresponding battery management system can perform both the online monitoring and battery charging tasks by the use of the same low-cost 8-bit microcontroller. Battery state-of-charge monitoring tests have been carried out under both constant and dynamic load conditions and for alternate charge-discharge cycles of lead-acid batteries of different capacities, and for different operating temperatures. The test results have shown that a very good accuracy (better than 3%-4%) in the estimation of available capacity is obtained for various charge-discharge strategies corresponding to practical operating conditions. Changes in battery characteristics which occur due to aging are also taken into account by estimating the actual capacity of the battery and adopting the corresponding recharacterization of the aged cells automatically.     

VRLA battery rapid charging under stress management

This paper discusses an approach for closed-loop charge control of valve-regulated lead-acid (VRLA) batteries used in telecommunication standby power applications. This is an alternative to conventional preprogrammed, configuration-driven charge control. The developed approach uses the battery's response to the supplied charge to control the recharge process. In this way, only the energy that can be absorbed by the battery in the desired recharge operation is dealt with. Hence, excessive energy that causes battery stress, or lack of energy that slows the charging process is avoided. Two main sources of recharge stress are identified: (a) thermal stress, and (b) charge saturation stress. A charge control algorithm based on thermal management and charge saturation avoidance is suggested. The algorithm utilizes a fuzzy state-of-charge estimation model that derives the state of charge from real-time parameters. This in turn calculates the maximum recharge rate that maintains the battery's thermal rise within permissible limits.