动力电池二次利用一致性分选研究

针对动力电池二次利用时单体电池不一致性影响电池储能系统整体性能的问题,研究长期使用后的退役动力电池关键参数的变化,分析现阶段动力电池的匹配成组筛选策略以及电池均衡算法,根据电池状态和参数变化信息选择合适的电池性能评价方法,通过对退役动力电池进行严格的筛选分组、均衡策略以维持整个电池组的一致性.研究表明,通过合理的电池匹...     

基于产线大数据的锂离子电池一致性动态特性分选方法

随着锂离子电池生产规模的迅速扩大,电池制造商急需高精度高效率的电池分选方法,增强电池成组后的一致性,从而提升电池组寿命、安全性和能量密度。基于容量和内阻等特性的传统分选技术可以满足成组后的静态一致性需求,但无法保证同组电池的动态一致性。因此,综合考虑电池在整个充放电过程中的性能,基于充放电电压曲线动态特性的分组方法是下一代分选技术的发展方向。本文基于电池产线大数据,从电池分容阶段的电压曲线提取关键动态特征,形成了基于K-means聚类的电池分选方法。此外,本文还从电池分容后的回充阶段提取了用于评估电池性能一致性的指标,并设计了一个以指标标准差为核心的电池一致性评价方法。与传统的电池分选方法相比较,本文方法分选后的电池综合性能一致性提高了15.65%。     

并联锂离子电池组建模及不均衡电流分析

近年来电池储能以其响应速度快、能量密度高等优点,在电力系统中发挥重要作用。为满足实际应用的要求,电池储能系统需要将电池或电池组并联从而达到较高的可用容量,但并联电池在实际中受内阻、容量、荷电状态（SOC）等影响将出现电流不平衡现象,一定程度上制约了电池充放电电流和使用条件,影响了电池性能。针对并联电池组支路电流采集过程繁琐且状态估计复杂的情况,以电池的二阶等效电路为基础,结合回路电流法建立了并联电池组的仿真模型。模型能够根据锂电池的性能参数及状态方程实现并联支路电流的计算,进而估计并联电池组的状态,省去了对并联支路电流的检测环节。同时重点研究了并联电池组的支路不均衡电流现象,以磷酸铁锂电池为例,分析了并联电池组的充电特性。针对并联电池组的支路不均衡电流影响因素较为复杂、难以解耦的特性,采用控制变量法,通过模型详细分析了内阻、容量、初始SOC等因素对支路电流点的影响,为并联电池组的设计、成组优化及性能分析提供了参考。     

储能锂电池模组温度场数值计算与散热系统优化设计

储能电池热失控是引发储能电站事故的主要因素之一,储能电池的热管理对电池使用效率、寿命以及运行安全具有重要意义。本文设计了以60系列大圆柱电池单体为基本单元、额定电量为11.52 kWh的储能电池模组,基于有限元方法建立了电池模组热流耦合数值计算模型,分析电池模组内部风道空气流速以及电池组温度场分布规律,并开展储能电池模组原型充放电温升试验,验证数值计算结果的准确性。进一步优化储能电池模组的温度场分布,通过调整散热孔排布方式对电池模组进行了优化设计,提出一种侧面U形开孔结构,储能电池模组的温度一致性和电芯最大温度得到了显著改善。优化后,模组电芯最大温差降低2.6℃,温度标准偏差降低1.18,研究结论可为储能电池模组温升计算与散热设计提供参考。     

电化学储能系统电池柜散热的影响因素分析

电化学储能系统是“双碳”目标实现的有利抓手,安全是电化学储能系统发展的生命线。由于大量电池存放于储能电池柜,因此对其散热性能的研究具有重要的意义。针对磷酸铁锂锂离子电池系统机柜：构建了电池系统数值模型,获得了电池柜内的温度场和气流组织,试验结果验证了模型的合理性;研究了进口风速、单体电池间距以及电池组间距对电池柜散热性能的影响规律,支撑储能机柜的设计和运维管理;结果表明,电池柜在低倍率运行情况下可采用自然对流冷却,高倍率运行情况下需要强制风冷策略;机柜最高温度和最大温差都随着单体间距增加呈现先减小后增大的趋势;电池组间距对电池柜散热性能影响不显著,因此可通过减小电池组间距来节省安装空间。     

考虑SOC的自适应分组策略在储能参与一次调频中的应用

大规模储能电站中各电池组状态的不一致性,使得传统电池参与一次调频研究时的归一化处理难以涵盖所有电池组状态,容易导致部分电池过度充放电。提出了一种考虑电池荷电状态（state of change, SOC）的自适应分组策略,用于储能参与一次调频的应用研究。根据电池的额定容量和SOC对储能电池进行分组,以实时调整各电池组的出力比例;设计评价指标以量化分析电池使用寿命,根据每组电池SOC对其进行综合控制,以实时调整每组电池出力大小,减小电池循环深度,提升其使用寿命。通过Matlab/Simulink进行仿真验证,结果表明,所提分组策略能在保证一次调频性能的同时,有效提升储能电池的使用寿命。     

锂离子电池建模现状综述

简述了我国用于大规模储能的锂离子电池建模技术的最新研究进展.由于储能技术可以起到平抑波动、提高电能质量的作用,所以近年来电网对于储能的需求也逐年增大.大规模储能系统由锂电池组、双向逆变器和电池能量管理系统组成,在双向逆变器和电池能量管理系统有现成可用模型的前提下,建立精确、可靠的锂离子电池模型便成了实现大规模储能工程应...     

Research progress in the consistency screening of Li-ion batteries

锂离子电池因综合性能优良,近年来在移动储能和固定储能领域的应用发展迅速。当多个单体电池通过串并联组成电池模组时,不仅电池组的能量低于电池单体能量的加和,电池组的寿命也明显低于单体电池的水平。除了电池运行环境不均匀（如温度场）外,电池组内部电池单体之间微小的不一致性也是造成电池组性能快速衰减的主要原因。依据电池组的结构建立电池一致性的筛选方法和标准,是目前锂离子电池模组研究中亟待解决的关键技术。本文回顾了近年来国内外锂离子电池一致性筛选方法研究领域的进展,对锂离子电池一致性的内涵进行了剖析,并重点对串联筛选方法进行了评述。     

大容量储能系统电池管理系统均衡技术研究

电池组一致性问题是大容量电池储能系统的重要问题,电池管理系统的均衡技术是解决这一问题的有效方法。对大容量储能系统中电池管理系统均衡技术进行了研究,分别介绍和探讨了电池模块内均衡技术、模块间均衡技术,以及电池系统中相内和相间均衡策略,并阐述了四级均衡体系的构建与实现。通过电池系统四级均衡体系的应用,实现了电池系统内不同层级的有效动态均衡,为更大容量的电池系统的长寿命和有效利用提供了技术支持。     

基于证据KNN分类器的蓄电池一致性诊断

通过串并联方式组成的大容量储能电站在长期运行过程中,会不可避免地出现电池单体不一致性的问题。及时识别出有可能存在异常的电池单体,为储能电站评估电池的健康状态提供数据支撑的同时,还可降低储能电站系统性运行风险。该研究提出一种不依赖于电池模型以及经验数据的,基于证据K近邻（KNN）分类器的储能电池一致性诊断方法。该方法利用储能电站一簇电池中的大量单体电池电压与温度运行数据,使用证据KNN分类器构建能表征电池电压、温度一致性的诊断模型,并通过异常反演算法,准确识别出异常的单体电池。     

纯电动船复合储能系统的设计与优化

针对纯电动船中的动力电池组易受瞬态大电流的冲击、使用寿命短等问题,提出以磷酸铁锂电池和超级电容为核心的复合储能系统方案,进行理论分析,并采用DC/DC变换器以更好地发挥超级电容性能。采用带精英策略的非支配排序遗传算法进行多目标优化选型,结合能量管理策略,实现储能系统的优化配置。仿真结果表明,得到的选型方案结合以模糊控制为核心的能量管理策略能够很好地应对波动性负载。     

Experimental and numerical investigation of heat transfer in Li‐ion battery pack of a hoverboard

Li‐ion cells are used for energy storage and conversion in electric vehicles and a variety of consumer devices such as hoverboards. Performance and safety of such devices are severely affected by overheating of Li‐ion cells in aggressive operating conditions. Multiple recent fires and accidents in hoverboards are known to have originated in the battery pack of the hoverboard. While thermal analysis and measurements have been carried out extensively on large battery packs for electric vehicles, there is relatively lesser research on smaller devices such as hoverboards, where the extremely limited thermal management design space and the critical importance of user safety result in severe thermal management challenges. This paper presents experimental measurements and numerical analysis of a novel approach for thermal management of the battery pack of a hoverboard. Measurements indicate that temperature rise in cells in the pack can be as large as 30°C at 4C discharge rate, which, although unlikely to be a standard discharge rate, may result from a malfunction or accident. A novel thermal management approach is investigated, wherein careful utilization of air flow generated by hoverboard motion is shown to result in significant temperature reduction. Measurements also indicate the key role of the metal housing around the battery pack in thermal management. Measurements are found to be in good agreement with finite element simulations, which indicate that the battery pack can be cooled as effectively in presence of a perforated metal casing as without the casing at all. Experimental data and simulation model presented here offer critical insights into the design of hoverboard thermal management and may result in safer, high performance hoverboard battery packs.     

智能微网中铅酸电池储能系统控制策略

介绍了铅酸电池储能系统组成,包括铅酸电池组、电池管理系统（BMS）和储能变流器（PCS）,对铅酸电池储能系统的并网PQ控制、离网v/F控制、并离网切换控制和恒压浮充控制等控制策略开展研究,在此基础上研制了250kW／800kW·h铅酸电池储能系统,应用于扬州经济技术开发区智能电网综合示范项目中,试验证明所采用的控制策略能够满足运行要求。     

光伏电力混合储能系统的能量管理策略研究

文章提出了一种光伏电力混合储能系统的能量管理控制策略,主要应用于含有光伏电源(Photovoltaic,PV)、电池能量存储(Battery Energy Storage, BES)和交流负载的发电网络系统中。该策略能够充分利用电力系统中组合架构之间的连接关系,有效缓解了目前电网中BES系统存在的过充电、欠充电等问题,并将充放电电流控制在一个相对稳定的范围内,延长了电池的使用寿命。分别在含有传统铅酸和锂离子电池的混合能量系统中使用6 kVA电源转换器进行实验,结果证明了所提出的能量管理策略的正确性和有效性。     

Analysis of Heat Dissipation Performance between a Horizontal and Longitudinal Battery Pack Based on Forced Air Cooling

A battery pack is the main energy storage element, and directly affects the performance of an electric vehicle. Battery thermal management system research and its development for a modern electric vehicle is required. This paper selects the forced air cooling of battery pack as the research object, and uses simulation methods to research the heat dissipation performance with different structures of battery packs. The results indicate that according to the four types of transient state conditions, the rising temperature of both battery packs are significantly higher than the temperature difference, the maximum temperature rise and temperature difference of a horizontal battery pack are lower than a longitudinal battery pack. When an electric vehicle begins to decrease speed, the curves of temperature rising and temperature difference increase. This shows the internal heat is continuously rising, so even in a electric vehicle beginning to decrease speed, the fan must work. The reference basis for choosing battery pack type and an analysis of heat flow field characteristics, including fan run‐time control, are offered.     

Photovoltaic grid stabilization system using second life lithium battery

The operation of residential solar photovoltaic arrays are typically dependent on net energy metering (NEM) tariffs or feed in tariffs that allow the array owner to treat the electricity grid as an energy storage device. This study presents a model and simulation results of a photovoltaic array paired with a second life battery pack, a partially degraded lithium battery pack from an automotive application, for stabilizing the electricity grid interactions of residential photovoltaic systems and reducing the overall residential demand placed on the electricity grid. Two numerical simulations are performed on the operation of a second life battery pack. The first used an equivalent system model for the battery pack and measured solar production and residential loads to evaluate the system performance using one second time steps. The second model used hourly time steps and round trip efficiency for the battery, coupled with weather data and residential demand, to determine the system performance over the course of a year. The numerical investigation shows that the PV and battery system can substantially reduce the quantity of solar electricity that is exported to the distribution grid and decrease the impacts of sudden fluctuations in photovoltaic output due to cloud cover while providing significant reductions in the electricity demand placed on the grid. Copyright © 2015 John Wiley & Sons, Ltd.     

Numerical analysis of an energy storage system based on a metal hydride hydrogen tank and a lithium-ion battery pack for a plug-in fuel cell electric scooter

This work investigates on the performance of a hybrid energy storage system made of a metal hydride tank for hydrogen storage and a lithium-ion battery pack, specifically conceived to replace the conventional battery pack in a plug-in fuel cell electric scooter. The concept behind this solution is to take advantage of the endothermic hydrogen desorption in metal hydrides to provide cooling to the battery pack during operation.The analysis is conducted numerically by means of a finite element model developed in order to assess the thermal management capabilities of the proposed solution under realistic operating conditions.The results show that the hybrid energy storage system is effectively capable of passively controlling the temperature of the battery pack, while enhancing at the same time the on-board storage energy density. The maximum temperature rise experienced by the battery pack is around 12 °C when the thermal management is provided by the hydrogen desorption in metal hydrides, against a value above 30 °C obtained for the same case without thermal management. Moreover, the hybrid energy storage system provides the 16% of the total mass of hydrogen requested by the fuel cell stack during operation, which corresponds to a significant enhancement of the hydrogen storage capability on-board of the vehicle.     

锂离子电池热安全防控技术的研究进展

在众多储能技术中,锂离子电池以其能量密度大、能量转换效率高、循环寿命长、应用范围广、对环境友好等优势,成为当前最具应用前景的电力系统电池储能技术之一。但现有锂离子电池体系无法从本质上保证其安全性,在使用过程中具有发生热失控乃至燃烧、爆炸等安全事故的风险。本文就锂离子电池的热失控机理、电池本体的安全设计、安全预警、电池组热失控起火的阻燃装置以及消防安全的研究进展进行了综述。     

磷酸铁锂电池及其新能源汽车启动电源性能研究

鉴于汽车启动电源铅酸电池存在严重环境污染隐患,本文采用环保型32650圆柱磷酸铁锂电池组装成25.6 V/65 A•h电池组代替铅酸电池应用于汽车启动电源,并分别对磷酸铁锂电池组的常温和低温启动能力、倍率性能和低温放电性能等进行测试。实验结果表明,电池组0.33 C放电容量为67.028 A•h,3 C放电容量为0.33 C放电容量的98.24%,电池组具有较好的倍率性能;电池组在 −30℃放电容量为额定容量的84.7%,具有良好的低温性能;电池组在25℃和 −20℃下以600 A电流放电,单串电池电压均高于放电保护电压;电池组在25℃搁置28 d之后,容量恢复率为99.37%;磷酸铁锂电池组性能均满足汽车启动电源性能要求,可以代替铅酸电池作为汽车启动电源。     

动力汽车用锂电池热管理系统仿真分析

为了研究动力汽车用锂电池温度场分布,建立了单体电池及电池组仿真模型,通过实验与FLUENT软件模拟验证的方式分析单体电池温度场。通过仿真分析讨论电池组温度场,采用三种不同的进出风方式进行空气强制冷却电池组,分析了进出风口有倾角与无倾角的不同温度控制效果,结果表明带有倾角的进出风方式有利于降低电池组最高温度。采用电池组壳体侧面开孔方式进行电池组热管理,可有效改善电池组放电过程的温度分布均匀性。