A method for compensating customer voltage drops due to nighttime simultaneous charging of evs utilizing reactive power injection from battery chargers

When we consider global warming, the reduction of CO₂ emissions is one of the most important issues which require urgent solutions. One option is to integrate low‐CO₂‐emission generators to the grid as much as possible. Another option is to replace ine?cient vehicles based on internal‐combustion engines with electric ones (EVs). Due to the latter, we can easily predict that most consumers will charge EVs' batteries during nighttime. Thus, excessive voltage drops due to nighttime simultaneous charging are expected to be a possible future problem. This paper proposes a method for compensating the voltage drops by injecting reactive power from EV battery chargers. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 19–29, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22390     

电动汽车动力电池模型及SOC预测方法

简要介绍了铅酸蓄电池的电化学过程,提出了一种考虑温度影响的动态R-Q电池模型,并在此基础上建立了一种新的基于状态空间的SOC递推算法。对电池的两种放电过程仿真计算表明,该算法精确可靠,计算速度快,易于实现,适合电动汽车上使用。基于状态空间的SOC预测方法通过电池稳态开路电压来计算SOC,在电池充放电循环过程中没有误差累积,同样可用于其它类型的动力电池。     

可再充锌空气电池的发展

简述了锌空气电池的优缺点。评述了可再充锌空气电池的各种充电方法。认为采用第三电极的充电法或双功能氧电极的锌空气电池 ,须解决充放循环过程中锌电极的变形和锌枝晶问题。讨论了锌空气电池电解液的吸湿与干涸的原因和电池放电时的发热与温升问题。阐述了可再充锌空气电池目前达到的水平。认为将该电池应用于电动车辆 ,还须在空气湿度的控制和电池放电时的热管理方面作进一步的工作。在工作电压不太高的场合 ,采用机械再充式锌空气电池是可行的     

电动车用MH/Ni电池的充放电特性

通过研究电动车用MH/Ni电池在不同的电流下的充放电特性、温度特性以及在不同SOC点的充电效率特性 ,为MH/Ni电池物理模型的建立 ,参数的识别以及MH /Ni电池在电动车上的应用提供实验依据。试验结果表明 :对于在电动汽车及混合动力汽车上的应用 ,MH/Ni电池比传统的铅酸电池具有更多优点。     

铅酸蓄电池充电接受能力及充电方式选择

通过分析麦斯三定律,指出铅酸蓄电池充电接受能力与放电电流及放电深度的关系.对机动车辆上使用条件不同的蓄电池应采用不同的充电方式:普通新蓄电池宜采用分级恒流充电;干荷电新蓄电池宜采用小电流恒流充电;大电流放电频繁的在用蓄电池宜采用恒压充电;大电流放电不频繁的在用蓄电池宜采用先恒流、后恒压充电;蓄电池储存期的维护性充电宜采用小电流恒流充电;电动车蓄电池宜采用脉冲去极化充电;放电情况不明的蓄电池应先放完电,再根据放电方式选择合适的充电方式.     

Performance Evaluation of Lithium‐Ion Batteries on Small Electric Bus

We evaluate performance of lithium‐ion batteries on the small electric bus, conducting tests of cell and battery pack using discharge/charge machine. We suggest the test item on distinction between good and bad of a battery. In the discharge/charge cycle tests of cell at environmental temperature (25 °C), the relative capacity was 60% at 10,000 cycles. In the discharge capacity test of battery packs on the small electric bus, the relative capacity maintained more than 90% in progress for approximately 900 days. Finally, based on these results, we analyzed about influence factor on a battery discharge capacity.     

梯次利用动力锂电池的单体电池电化学性能

随着电动汽车的快速发展,大量车用动力锂电池面临退役。对退役动力锂电池进行合理的梯次利用,可以降低动力锂电池的全寿命周期成本,提升动力锂电池的利用价值,对电动汽车行业的快速发展具有重大意义。将退役的车用动力锂电池包进行拆卸,对其单体电池外观和电化学性能进行测试,测试结果表明:单体电池的外观尺寸符合要求,开路电压压差值较小,内阻极差值达12.66 mΩ,容量衰减较为严重,在1 C下放电温升高达56℃,贮存28天后的容量保持率为89.4%。     

基于参比电极的析锂电池安全充电控制

电池系统是支撑下一代新型电网的关键,然而随着使用次数增加电池性能会逐渐衰减,导致充放电能力大幅减弱。因此,本文针对三元锂离子电池,通过制备参比电极,揭示了不同温度充放电循环后电池充电性能变化。首先,设计了不同温度下的充放电循环实验,得到低温循环与高温循环两种状态下的电池;其次,通过植入参比电极标定安全充电曲线对比不同状态电池的负极电位情况,发现高温循环后的电池发生了析锂,并且在300 A电流充电持续时间上对比新鲜电池降低了76.19%;最后,对析锂后的电池建立了安全充电荷电状态-温度-电流等高线图。对比新鲜电池后发现,相同温度和荷电状态区间电池200A以上的充电能力减少了69.84%。电池发生析锂副反应后会严重影响电池充电性能,需要在实际的锂离子电池全寿命周期管理中予以考虑。     

热电池热模型的研究

从热电池的基本工作原理出发,研究了热电池放电过程中热量的产生、传递、散失变化特征.并通过计算机软件,将电池模型进行网格划分,依据热量平衡原理,建立电池的热传导方程,利用"有限元法"动态模拟电池放电热过程特征与规律.并通过对电池表面以及内部温度测量进行比较分析,证明了该热模型能够正确地模拟电池放电过程的温度变化.     

6GFM-200蓄电池高倍率充/放电性能测试

为满足15～1 000 ms的50～80T脉冲磁场的供电参数要求,对6GFM-200阀控式铅酸蓄电池组分别进行了不同负载下高倍率充/放电性能、高倍率充/放电循环、高倍率放电状态下蓄电池内阻等测试。实验结果证明：蓄电池在4 000次2 000 A/1.5 s的高倍率充/放电循环过程中,尽管蓄电池内阻随着剩余容量衰减而增大,但蓄电池工作电压始终保持在12.87～13.80 V之间,蓄电池没有发生发热、膨胀、失效的现象。     

炭黑含量对铅酸蓄电池负极性能的影响

采用充放电技术研究了电动车用阀控铅酸蓄电池负极的炭黑含量对电池容量、充电接受能力及充电方式的影响,结果表明负极中添加适量的炭黑可以改善电池负极的导电性能,提高电池的负极活性物质利用率及电池的放电容量,有利于电池的大电流放电,提高电池的充电接受能力及循环寿命,并对充电方式的敏感性小。电动车用阀控铅酸蓄电池负极炭黑添加量在0.9%左右时表现出最佳的充放电性能。     

混合电动汽车用氢镍电池热控制技术研究

混合电动汽车用MH-Ni电池组是由上百只单体电池进行组合而成的,电池组在频繁的大电流使用过程中,会不断地产生热量;分析了MH-Ni电池在充、放过程中产生热量的3个主要途径,并从提高电池的高温充放电效率、减小欧姆电阻的影响、降低电池的产热速率和产热量,以及如何对电池强制散热、减少电池的热量累积等方面介绍了MH-Ni电池热控制技术的研究现状。     

变电流间歇快速充电法

本文已建立变电流间歇快速充电法,它对VRLA蓄电池在电动车应用方面具有重要意义。它的法参数有初始电流、转换电压、停充时间、变电流方式等,并通过试验给出这些参数。它与标准充电方比较,充电时间缩短,且给出更多放电容量。在间歇充电中采用变电流方式比脉冲电流好。变电流间歇电时间190min,放电容量92％,而脉冲电流间歇充电时间为290min,放电容量为87％。电池荷电态和度影响已讨论。快速充电用于循环试验时,经几次循环后要用标准充电法将电池恢复至完全充电态。     

电动车辆用超级电池的研究试验

为提高电动车辆用电池的比功率和高倍率放电循环寿命,在铅酸蓄电池的负极群中并入活性炭极板,制成了超级电池.这种电池的铅负极板不易硫酸盐化、大电流充/放电特性好.对超级电池放电容量、模拟电动助力车实际运行工况的充/放电循环的测试结果表明,这种内并结构的超级电池能够明显改善性能.     

A novel charging/discharging balancing strategy for lithium battery pack based on mixed charging mode

Series‐connected lithium batteries can be charged in the pack‐charging mode, which is most widely used in the lithium battery application field. But the pack‐charging mode will lead to cell imbalance because of the difference in the electrochemical characteristics of the cells of series‐connected batteries. On the other hand, the cell‐charging mode can avoid the imbalance problem by charging each cell independently, but it will reduce the charging efficiency and increase the cost. In this paper, a novel balancing strategy is proposed with a mixed pack‐charging and cell‐charging mode to implement the balancing algorithm. The proposed strategy aims to solve the problem of charge/discharge imbalance with the simplest balancing algorithm with high balancing performance. There is no complex balancing behaviors during the charging process – as is the case with many other existing schemes – so the control algorithm can be greatly simplified. Because each cell can be fully charged and discharged with the proposed algorithm, it helps to make full use of the energy and capacity of each cell. The system stability and reliability of the proposed system, as well as its good performance, are verified through experiments. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

便携式锂电池组单体电压在线主动均衡系统

针对锂电池组充放电过程中的单体均衡问题,基于实时单体参量高精度检测与快速反馈调节原理,设计并实现了一种便携式锂电池组单体电压在线主动均衡系统。该系统在蓄电池组使用过程中的实时采集电压、电流、温度等电池参量,通过蓄电池组总电压给单体充电的方式,实现了蓄电池组各个单体过充、欠充、过放、过温条件下单体问的均衡,系统整体尺寸为160＊60＊105mm,配备于蓄电池组进行在线均衡调节。实验结果表明,该系统能够实现9只单体的实时主动均衡,尖峰电流均衡响应时间在300s左右实现各个单体之间的电压不平衡度低于5％,达到蓄电池组现场应用中实时主动均衡进而保证安全供能的目标。     

锂离子电池放电过程瞬态生热特性分析

为探索纯电动汽车用锂离子电池在放电过程中的瞬态热特性,通过试验测试得到不同温度下的内阻和不同放电倍率下的温升曲线,计算出不同放电倍率下的瞬时生热率;根据0.5C放电倍率下的瞬时生热率和内阻生热率,求出熵热(可逆反应热)系数变化曲线,分析锂离子电池熵热特性对瞬态生热特性的影响。分析结果表明:锂离子电池的瞬态热特性主要受电池内阻热和熵热(可逆反应热)的瞬态特性影响;熵热是影响电池放电过程中温度波动的主要因素,在放电中期会出现由相变反应引起的吸热现象;在小倍率放电过程中,熵热对电池温度场的影响大于内阻热,而在大倍率中则相反。通过分析,可以为电池瞬态生热模型的建立与完善提供依据。     

Potential estimation of hourly blank storage space and charge loads of EVs using road traffic census and vehicles status

If both EVs (Electric Vehicles, includes plug‐in hybrid electric vehicles) and renewable energies spread in large quantities, it is possible to control the supply fluctuation of renewable energies using the storage battery of EVs. This research sought to show the charge load potential of EVs based on the state of the Japanese passenger car using traffic census results, etc. Furthermore, it tried to show the trend of the storage battery capacity according to time. From the estimated results: (1) the charge electricity of low and middle distance gets a majority of the total charge demand, (2) charge load changes according to time several times, and the minimum load is the number of gigawatt‐hours at early morning, (3) if night charge is assumed, the standby charge demand of noon will reach tens of gigawatt‐hours, it may have sufficient scale for supply fluctuation control of PVs. Although the present EV is not suitable for long‐distance running, these are expected to be 30 or less percent of the total charge demand. The estimated storage capacity potential in this research will not change numbers of times. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(3): 30–38, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22352     

电动车用MH-Ni电池温度特性研究

工作温度是影响大容量MH—Ni电池充放电性能的重要因素。针对电动车用MH-Ni电池的特点,阐述了该电池高温和低温性能差的原因和解决办法;分析了高温和低温对放电容量和充电效率的影响;试验了高温和低温对自放电和循环寿命的影响,为MH-Ni电池在电动车中的实际应用提供了实验数据。