An analytical model for predicting the remaining battery capacity of lithium-ion batteries

Predicting the residual energy of the battery source that powers a portable electronic device is imperative in designing and applying an effective dynamic power management policy for the device. This paper starts up by showing that a 30% error in predicting the battery capacity of a lithium-ion battery can result in up to 20% performance degradation for a dynamic voltage and frequency scaling algorithm. Next, this paper presents a closed form analytical expression for predicting the remaining capacity of a lithium-ion battery. The proposed high-level model, which relies on online current and voltage measurements, correctly accounts for the temperature and cycle aging effects. The accuracy of the high-level model is validated by comparing it with DUALFOIL simulation results, demonstrating a maximum of 5% error between simulated and predicted data.     

Intelligent control battery equalization for series connected lithium-ion battery strings

An intelligent battery equalization scheme based on fuzzy logic control is presented to adaptively control the equalizing process of series-connected lithium-ion batteries. The proposed battery equalization scheme is a bidirectional dc-dc converter with energy transferring capacitor that can be used to design the bidirectional nondissipative equalizer for a battery balancing system. Furthermore, it can be designed as a ripple-free converter for improving the input current distortion of the battery charge supply power system. A fuzzy-logic-controlled strategy is constructed with a set of membership functions to prescribe the cells equalizing behavior within a safe equalizing region for rapid cell voltage balancing. The simulation and experimental results show the advantage of the predicted equalizing performance of the lithium-ion battery stacks. The proposed fuzzy logic control battery equalization controller can abridge the equalization time about 32%. The proposed method maintains safe operation during the charge/discharge state in each lithium-ion cell of the battery strings.     

大容量锂离子电池储能系统散热研究

基于锂离子动力电池生热模型仿真与实验的研究,对局部强化射流冷却散热系统开展了储能系统电池模块不同充放电倍率下的流热数值仿真,实现了电池模块储能系统在不同工况下热行为仿真。研究结果表明:局部强化射流冷却散热系统能够有效降低电池温度,但是随着充放电倍率的增大,电池模块温度升高,各单体电池之间的温差增大,不利于单体之间的协调性和电池模块性能的发挥,进而影响其安全性和可靠性。     

动力锂离子电池部分荷电和深度放电状态下的脉冲充电技术

针对动力锂离子电池的使用特点和其自身的充放电特性,以提高其充电效率,延长循环寿命为目的,设计制造了间歇-正负脉冲智能充电器,实现了正、负脉冲交替充电。模拟部分荷电和深度放电的实际使用特点,进行不同的充电模式循环对比实验,同时对失效单体电池进行了容量恢复实验。实验中对电池进行正负级电位测量分析,验证对其结构的恢复作用,并对修复结果稳定性进行验证。实验结果表明,间歇-正负脉冲充电提高了正负极的活性,抑制了浓差极化的形成,且修复结果稳定,从而有效提高了电池的循环寿命。     

Dynamic model of communicating hydrocephalus for surgery simulation

We propose a dynamic model of cerebrospinal fluid and intracranial pressure regulation. In this model, we investigate the coupling of biological parameters with a 3-D model, to improve the behavior of the brain in surgical simulators. The model was assessed by comparing the simulated ventricular enlargement with a patient case study of communicating hydrocephalus. In our model, cerebro-spinal fluid production-resorption system is coupled with a 3-D representation of the brain parenchyma. We introduce a new bi-phasic model of the brain (brain tissue and extracellular fluid) allowing for fluid exchange between the brain extracellular space and the venous system. The time evolution of ventricular pressure has been recorded on a symptomatic patient after closing the ventricular shunt. A finite element model has been built based on a computed tomography scan of this patient, and quantitative comparisons between experimental measures and simulated data are proposed.     

Dynamic electric arc model for electronic circuit simulation

The authors present a physics based electric arc model which can simulate both static and dynamic characteristics of an arc load controlled by an electronic circuit. The proposed model was developed from modifications of the classical Cassie and Mayr equations. It has been test implemented in the Saber circuit simulator. There has been a considerable degree of correspondence between the simulated and experimental results     

碳纳米管在锂离子电池正极中的应用研究

以碳纳米管及Supper-p/KS-6作为正极导电剂分别制作了锂离子电池.利用SEM研究了电池电极的显微结构,并对电池的电化学性能进行了综合评价.结果表明,与Supper-p/KS-6导电剂相比,碳纳米管导电剂有效降低了电池内阻,显著提高了电池在大倍率情况下的性能,并改善了电池的循环性能:内阻从120 mΩ降到了100 mΩ,10.0C(C为放电倍率)及15.0C时的放电容量分别为0.5C时的90.4％和80.7％,500次循环后的容量保持率达89.0％.     

锂动力电池寿命预测研究进展

综述了国内外对于锂动力电池储存寿命和循环寿命预测模型的研究进展。阐述了以容量衰减、电阻增加与衰退为基础建立的寿命预测模型的研究成果。统一储存寿命和循环寿命预测,并综合考虑我国动力电池使用条件和外部环境情况,这对锂动力电池的应用具有现实意义。     

基于MAX1758的智能锂离子电池充电器设计

MAX1758是Maxim公司生产的锂离子电池充电器,可实现智能充电,自动监测调节电流、电压、温度等参数,为锂离子电池充电器提供了一种新的安全、高效的设计方案.给出了硬件电路和软件流程.     

面密度对锂离子电池快充性能的影响研究

面密度是影响锂离子电池快充性能的主要因素之一。采用扫描电子显微镜、X射线衍射仪及粒度分析表征正负极材料形貌和结构,研究不同面密度镍钴锰酸锂/石墨锂离子电池的内阻、倍率性能、循环寿命和安全性能。结果表明,电池的内阻随着面密度的增加而增大,正极面密度从190 g/m~2提高到340 g/m~2,电池均呈现出良好的5C快速充放电性能和安全性能。正极面密度不超过280 g/m~2时,电池依然保持优异的10C快速充放电性能,容量达到1C倍率的93.4%以上。正极面密度为250 g/m~2的电池展示出最佳的5C倍率充放电寿命,2000次充放电后的容量保持率高达98.1%。而正极面密度为340 g/m~2的电池5C倍率充放电寿命衰减较快。     

国内外锂离子动力电池相关标准对比分析

由于锂离子电池具有比能量高、比功率大、循环性能好、工作范围宽等优点,近年来被大量应用于纯电动汽车和混合动力汽车中。总结了国内外锂离子动力电池近期的相关标准ISO 12405系列、IEC 62660系列、SAE J 2929、UL 2580、VDA 2007以及QC/T 743-2006,并对各标准的测试内容、测试范围、测试结果判定准则、暂存问题和展望等进行了归纳分析。     

基于COMSOL锂离子动力电池包的边界结构优化

对于以锂离子电池作为动力来源的新型装备而言,在电池包的设计过程中需要注意散热问题。针对这一问题,通过对常规电池包的结构模型进行合理的简化,分析并选择合适的空气流场模型,用COMSOL建立计算机仿真模型;通过对电池包不同的边界结构和不同的流场环境下电池散热性能进行模拟仿真;通过对仿真结果的后处理和数据分析,发现在进风口风速相等的情况下,带有波浪形凹凸鼓包边界的电池包在强制对流散热过程中,其相比于平直边界的电池包具有单体电池之间温差小、电池周围空气平均流速较大、整体散热效果好的优点。     

Meal simulation model of the glucose-insulin system

A simulation model of the glucose-insulin system in the postprandial state can be useful in several circumstances, including testing of glucose sensors, insulin infusion algorithms and decision support systems for diabetes. Here, we present a new simulation model in normal humans that describes the physiological events that occur after a meal, by employing the quantitative knowledge that has become available in recent years. Model parameters were set to fit the mean data of a large normal subject database that underwent a triple tracer meal protocol which provided quasi-model-independent estimates of major glucose and insulin fluxes, e.g., meal rate of appearance, endogenous glucose production, utilization of glucose, insulin secretion. By decomposing the system into subsystems, we have developed parametric models of each subsystem by using a forcing function strategy. Model results are shown in describing both a single meal and normal daily life (breakfast, lunch, dinner) in normal. The same strategy is also applied on a smaller database for extending the model to type 2 diabetes.     

基于神经网络与UKF结合的锂离子电池组SOC估算方法

锂离子电池组作为电动汽车的主要动力能源,对荷电状态的准确估计是电动汽车的关键技术之一。准确的SOC估计,对锂离子电池组的寿命维持及电动汽车的行车安全,具有十分重要的意义。基于此设计一种基于神经网络与无迹卡尔曼滤波器(UKF)相结合的SOC估算方法,既克服了UKF需要等效电池组电路模型的缺点,也能显著减小神经网络估算方法的最大误差。该实验数据来源于高级车辆仿真器(ADVISOR2002)基于实际工况的仿真结果,经实验数据证明,该方法具有有效性和实用性。     

矿用锂离子蓄电池电源安全性能试验要求变化浅析

锂离子蓄电池电源作为可靠的供电设备已经广泛的应用于煤矿井下,但由于锂离子电池存在的安全问题,使其在煤矿领域的应用受到很大限制。大容量锂离子电池电源在煤矿井下应用的安全性问题更是重中之重。为把好矿用锂离子蓄电池电源产品在该领域的准入关,国家相继制定新相关要求,来严格生产和检验。文章阐述了矿用锂离子蓄电池电源安全性能试验要求的几点变化,分析了变化的原因和考核针对物质。对落实新要求有着积极作用。     

OA系统中的动态工作流模型分析

针对办公业务流程的多变性，研究了工作流技术在OA系统中的应用，对WFMC定义元模型作了适当的扩展，使之能够实现OA系统中工作流的动态管理。提出并建立了该工作流系统的数学模型。     

动态电源路径管理简化了太阳能板对电池的充电

太阳能电池通常是由p-n结组成的,入射光线能量(光子)通过导致p-n结电子和空穴的重新组合来产生电流.由于p-n结的特性类似于二极管的特性,因此我们通常以如图1所示的电路作为太阳能电池特性的一个简化模型.     

基于DSP的动力锂电池检测系统

设计了一种基于TMS320C2812DSP的动力锂电池组检测系统,实现对锂电池组的单体电压、电流和温度的检测及显示。对电压、电流和温度的采集电路进行了具体的设计并进行详细的介绍。运算放大器采用ADI公司的AD708JNZ,电流互感器采用LEM公司的LA55-P/SP50。最后给出了检测系统的实验结果并进行分析。结果表明,该系统具有精度高、硬件电路简单、处理速度较快等特点,可以运用在电动车及混合动力系统的锂电池储能系统中。     

Dynamic hybrid model of an electro-pneumatic clutch system

This paper deals with modelling an electro-pneumatic clutch system, which is used for medium- and heavy duty commercial vehicles. The mathematical model is built up for dynamic simulation, parameter estimation and control design/validation purposes, which is a phase of the design process of a new clutch system. These intended applications define the modelling goals and determine the modelling assumptions, which let one to reduce the model complexity. Since the model shows discrete–continuous behaviour, i.e. the model has hybrid properties, a nominal state domain or hybrid mode has been chosen for the sake of simplicity, where the model is continuous. In addition all the cases are given systematically, where the model has discrete transients. The model is constructed on the basis of the conservation principles such as mass, energy, momentum and magnetic linkage conservation and it is provided with constitutive equations to get a solvable set of equations. This final collection is then transformed into state space form for the given applications above. The verification of the developed model is carried out using extensive simulations against engineering perception and operation experience on the qualitative behaviour. Then for validation purposes the outputs of the model are compared to measurements on the real system to give a quantitative performance index about the model accuracy. Since for model-based controller design the developed model is too complex it should be simplified. Hence possible model reduction methods are proposed, which omit all details that are weakly represented in the state variables/outputs and not coupled with the control aims.