温度自适应SMO算法估计锂离子电池的SOC

现有对锂离子电池荷电状态(SOC)的估计,没有考虑温度变化导致的SOC估计准确度降低。提出一种考虑温度的滑模观测(SMO)法进行SOC估计。基于混合脉冲功率测试(HPPC)实验的数据,得到18650型LiFePO4锂离子电池的SOC与温度、参数之间的拟合式,通过台风(Typhoon)系统进行半实物实验分析。温度自适应SMO算法在低温或常温工况下的平均误差较传统SMO算法降低0.3~0.5个百分点,直接通过拟合式所快速估计的SOC较温度自适应SMO算法平均误差在2%左右,常温25℃工况下误差低于1%,能够实现较高的估计精准度,为快速估计SOC提供了较好的算法参考。

Spinel lithium titanate (Li_4Ti_5O_(12)) as novel anode material for room-temperature sodium-ion battery

This is the first time that a novel anode material, spinel Li4Ti5O12 which is well known as a ＂zero-strain＂ anode material for lithium storage, has been introduced for sodium-ion battery. The Li4Ti5O12 shows an average Na storage voltage of about 1.0 V and a reversible capacity of about 145 mAh/g, thereby making it a promising anode for sodiumion battery. Ex-situ X-ray diffraction （XRD） is used to investigate the structure change in the Na insertion/deinsertion process. Based on this, a possible Na storage mechanism is proposed.

Unlock the potential of Li4Ti5O(12) for high-voltage/long-cycling-life and high-safety batteries: Dual-ion architecture superior to lithium-ion storage

Li4Ti5O(12)(LTO)has drawn great attention due to its safety and stability in lithium-ion batteries(LIBs).However,high potential plateau at 1.5 V vs.Li reduces the cell voltage,leading to a limited use of LTO.Dual-ion batteries(DIBs)can achieve high working voltage due to high intercalation potential of cathode.Herein,we propose a DIB configuration in which LTO is used as anode and the working voltage was 3.5 V.This DIB achieves a maximum specific energy of 140 Wh/kg at a specific power of 35 W/kg,and the specific power of 2933 W/kg can be obtained with a remaining specific energy of 11 Wh/kg.Traditional LIB material shows greatly improved properties in the DIB configuration.Thus,reversing its disadvantage leads to upgraded performance of batteries.Our configuration has also widened the horizon of materials for DIBs.

An ultrathin and continuous Li_4Ti_5O_(12) coated carbon nanofiber interlayer for high rate lithium sulfur battery

Severe capacity fading and poor high rate performance of lithium sulfur(Li–S) battery caused by "shuttle effect" and low conductivity of sulfur hampers its further developments and applications. Li_4Ti_5O_(12) (LTO)possesses high lithium ion conductivity, and it is also can be used as an active adsorbent for polysulfide. Herein, fine LTO particle coated carbon nanofibers(CNF) were prepared and a conductive network both for electron and lithium ion was built, which can greatly promote the electrochemical conversion of polysulfide and improve the rate performance of Li–S batteries. Meanwhile, a quantity of adsorption sites is constructed by defects of the surface of LTO-CNF membrane to effectively immobilize polysulfide. The multifunctional LTO-CNF interlayer could impede the shuttle effect and enhance comprehensive electrochemical performance of Li–S batteries, especially high rate performance. With such LTO-CNF interlayer,the Li–S battery presents a specific capacity of 641.9 mAh/g at 5 C rate. After 400 cycles at 1 C, a capacity of 618.0 mAh/g is retained. This work provides a feasible strategy to achieve high performance of Li–S battery for practical utilization.

基于EKF算法的纯电动汽车锂电池SOC与SOH联合估算

为提高对动力电池的荷电状态(state of charge, SOC)估算精度、动力电池的健康状态(state of health, SOH)对锂电池性能的影响,提出一种扩展卡尔曼滤波(extended kalman filtering, EKF)联合估算算法。根据现有的实验数据,分析锂电池特性,构建二阶RC等效电路模型,并进行参数辨识,搭建MATLAB仿真平台联合EKF算法进行SOC估算,将仿真结果与真实数据进行对比,结果表明,EKF联合估算SOC比EKF估算SOC误差精度约高1.2%,且抗干扰能力更强。

基于IGWO-BP神经网络锂电池SOC估算

针对传统BP神经网络估算电池SOC过程中,存在初始权值和阈值对预测精度影响较大的问题,引入Tent混沌映射和自适应收敛因子对灰狼算法(GWO)进行改进,改善灰狼算法易陷入局部最优、后期迭代效率不高的缺点。将改进灰狼算法(improved grey Wolf algorithm,IGWO)与BP神经网络模型结合,得到BP神经网络最优初始权值和阈值,提高预测精度和收敛速度。对锂电池充放电实验数据预处理,得到样本数据。利用MATLAB进行仿真验证,结果表明,IGWO-BP神经网络算法的预测精度相较于传统BP神经网络算法、GWO-BP神经网络算法更优,基于改进灰狼优化BP神经网络估算电池SOC的方法的绝对误差能控制在1.53%以内,有效提高了预测精度和收敛速度。

Factors affecting specific capacity and rate performance of aqueous Li4Ti5O12 battery

The use of an aqueous slurry in the manufacture of lithium ion batteries has the advantages of being environmentally friendly,harmless to the human body,and low in production cost.In this study,the factors affecting the specific capacity and rate performance of the aqueous Li4Ti5O12 battery were studied,including the Li4Ti5O12 structure,aqueous binder,conductive agent,and surface density.The results show that a spherical secondary particle structure of Li4Ti5O12 is beneficial to its discharge rate performance.In addition,an aqueous binder with high conductivity improves the specific capacity and high rate charge/discharge performance of the battery,and when the amount of binder is 3%,the Li4Ti5O12 battery performs better.A chain structure in the conductive agent also improves the specific capacity and discharge rate performance of the Li4Ti5O12 battery,and increases the degree to which the discharge rate performance of the conductive agent can be further improved.Lastly,the lower the surface density,the better the rate performance of the Li4Ti5O12 battery.

HEV用功率型三元锂电池SOC估算模型及验证方法研究

准确预测动力电池SOC是混合动力汽车产品技术开发的难点,文章介绍一种基于功率型三元锂电池的电池等效模型的SOC估算方法。基于Ah积分结果运算电池SOC,并通过龙伯格方程修正实现SOC估算误差收敛。试验结果表明,25℃下该方法预测功率型三元锂电池的平均误差≤4%,实现SOC误差收敛,满足大部分电池系统SOC估算精度要求。

锂离子蓄电池负极材料Li_4Ti_5O_(12)的研究进展

对Li4Ti5O12 的结构与电化学性能的关系、制备方法、掺杂改性研究现状等进行了介绍。锂离子蓄电池负极材料锂钛复合氧化物———Li4Ti5O12 相对于锂电极的电位为 1.5 5V ,理论容量为 175mAh/ g ,实验容量为 15 0～ 160mAh/ g。在Li+ 嵌入和脱出的过程中 ,其晶型不发生改变 ,有很小的收缩和膨胀 ,体积变化小于 1% ,被称为“零应变”材料。以该材料为负极的锂离子蓄电池具有很好的循环性能 ,同时相对于石墨等碳负极 ,安全性和可靠性也得以大大改善 ,具有应用在电动汽车、储能电池等方面的优良前景 。

富锂尖晶石Li_4Mn_5O_(12)的合成

采用溶胶 凝胶法合成了富锂尖晶石Li4Mn5O12 ,研究了工艺条件对产物物理性能及晶体结构的影响。利用TGA DTA对其进行热分析 ,XRD ,SEM ,ICP等多种分析手段对产物进行了结构特征的表征。结果表明 :用柠檬酸做配合剂 ,最佳 pH值为 6 5 ,3 0 0℃焙烧 8h可合成纯相尖晶石Li4Mn5O12 ,形貌较好 。

反应气氛对Li_4Ti_5O_(12)/C复合材料性能的影响

以葡萄糖为碳源,采用固相法制备了Li4Ti5O12/C复合材料。探讨了不同反应气氛(N2/O2)对材料物理性质及电化学性能的影响,并通过XRD、SEM、BET、电导率、电性能等测试手段对其进行了表征。结果表明,N2气气氛中烧结的样品粒度、比表面积、电导率均比空气中烧结样品大。N2气中烧结样品的倍率性能优于空气中烧结样品,在以0.1C倍率充放电时,首次放电比容量为166.8mA.h/g。2种样品在1C时,经过50次循环容量保持率差别不大。

双功能仿生膜修饰改性Li_4Ti_5O_(12)负极材料

采用简单有效的自聚合方法在Li_4Ti_5O_(12)颗粒表面包覆兼具离子导电和电子导电双重功效的聚多巴胺(PDA)/导电碳黑Super P(SP)复合包覆层,获得了电化学性能优异的锂离子电池负极材料.利用X射线粉末衍射(XRD)、扫面电子显微镜(SEM)、透射电子显微镜(TEM)、充放电循环曲线和循环伏安(CV)等方法对复合材料的形貌、结构以及电化学性能进行表征.结果表明,当PDA包覆层的厚度为10 nm、Super P的含量为3%(质量分数)时,得到的包覆材料展示了优异的电化学性能:0. 2C倍率下初始放电容量为175m A·h/g,循环150周后,可逆放电容量仍在160 m A·h/g以上.

LiNi_(x)Co_(y)Al_(z)O_(2)锂离子电池SOC估算及衰减特性

以LiNi_(x)Co_(y)Al_(z)O_(2)(NCA)体系锂离子电池为研究对象,建立具有多工况下普适性的开路电压(OCV)-荷电状态(SOC)曲线,估算电池在不同工况下的SOC。研究电池在变工况(1.00 C倍率循环、1.50 C转1.00 C倍率循环、2.00 C转1.00 C倍率循环等)下,正极活性材料容量(Qp)、负极活性材料容量(Qn)及活性锂容量(QLi)的变化趋势。在变工况条件下,相同低倍率工况(1.00 C倍率)的Qn和QLi衰减趋势相对一致。

Engineering a flexible and mechanically strong composite electrolyte for solid-state lithium batteries

Lithium-ion batteries(LIBs)have greatly facilitated our daily lives since 1990s[1,2].To meet the ever-increasing demand on energy density,Li metal is seen as the ultimate anode because of its ultra-high specific capacity(3860 m Ah/g)and the lowest electrochemical potential(-3.04 V vs.the standard hydrogen electrode)[3–6].However,issues of Li metal anode,such as Li dendrite formation and large volume change during plating/stripping。

Kinetics of synthesis of Li_4Ti_5O_(12) through solid-solid reaction

Sohd-solid reaction under low heat or low temperature is an approach to synthesize various kinds of materials that were widely used in electrochemistry field. In this paper a theoretical treatment has been presented for analyzing the mechanism of sohd-solid reaction and deriving a series of formulae to describe the variation and rate of reactions. This new model has been used in the manufacturing of spinel Li4Ti5O12. The results show that this new model works very well and will play a useful role for guiding the manufacturing of electrochemical materials.

Enhancing interfacial stability in solid-state lithium batteries with polymer/garnet solid electrolyte and composite cathode framework

The solid-state lithium battery is considered as an ideal next-generation energy storage device owing to its high safety,high energy density and low cost.However,the poor ionic conductivity of solid electrolyte and low interfacial stability has hindered the application of solid-state lithium battery.Here,a flexible polymer/garnet solid electrolyte is prepared with poly(ethylene oxide),poly(vinylidene fluoride),Li6.75La3 Zr1.75Ta0.25O12,lithium bis(trifluoromethanesulfonyl)imide and oxalate,which exhibits an ionic conductivity of 2.0 ×10^(-4) S cm^(-1) at 55℃,improved mechanical property,wide electrochemical window(4.8 V vs.Li/Li+),enhanced thermal stabilities.Tiny acidic OX was introduced to inhibit the alkalinity reactions between Li6.75La3 Zr1.75Ta0.25O12 and poly(vinylidene fluoride).In order to improve the interfacial stability between cathode and electrolyte,an Al2 O3@LiNi0.5Co0.2Mn0.3O2 based composite cathode framework is also fabricated with poly(ethylene oxide) polymer and lithium salt as additives.The solid-state lithium battery assembled with polymer/garnet solid electrolyte and composite cathode framework demonstrates a high initial discharge capacity of 150.6 mAh g^(-1) and good capacity retention of 86.7% after 80 cycles at 0.2 C and 55℃,which provides a promising choice for achieving the stable electrode/electrolyte interfacial contact in solid-state lithium batteries.

基于多方法融合的锂离子电池SOC-SOH联合估计

健康状态估计对电池的实用性和经济性具有指导意义.针对电池健康状态估计难度大且估计结果极易受噪声的影响,但融合算法估计效果好且受噪声影响小,提出了基于粒子群优化深度置信网络和自适应扩展卡尔曼/自适应H_(∞)滤波((PSO-DBN)-AEKF/AHIFF)融合算法在卷积神经网络(CNN)模型下的锂离子电池SOC-SOH联合估计.首先对于健康状态(SOH)数据的预处理环节采用小波变换的方法使得噪声显著去除.其次将去噪后的数据代入训练好的CNN模型进行SOH估计,并融合((PSO-DBN)-AEKF/AHIFF)算法进行健康状态估计,最后在DST工况和UDDS工况下,搭建Matlab/Simulink/Python环境下的Typhoon HIL602+硬件在环平台进行联合估计的验证,结果显示健康状态的估计误差在1%以内,荷电状态(SOC)的估计误差在2%以内,由此证明了多方法融合的SOC-SOH联合估计的有效性,且具有较好的估计精度和鲁棒性.

Preparation and characterization of SnO_2-Li_4Ti_5O_(12) composite by sol-gel technique

SnO2-Li4Ti5O12 was prepared by sol-gel method using tin tetrachloride,lithium acetate,tetrabutylorthotitanate and aqueous ammonia as starting materials.The composite was characterized by thermogravimertric(TG)analysis and differential thermal analysis(DTA),X-ray diffractometry(XRD)and transmission electron microscopy(TEM)combined with electrochemical tests.The results show that SnO2-Li4Ti5O12 composite derived by sol-gel technique is a nanocomposite with core-shell structure, and the amorphous Li4Ti5O12 layer with 20?40 nm in thickness is coated on the surface of SnO2 particles.Electrochemical tests show that SnO2-Li4Ti5O12 composite delivers a reversible capacity of 688.7 mA·h/g at 0.1C and 93.4%of that is retained after 60 cycles at 0.2C.The amorphous Li4Ti5O12 in composite can accommodate the volume change of SnO2 electrode and prevent the small and active Sn particles from aggregating into larger and inactive Sn clusters during the cycling effectively,and enhance the cycling stability of SnO2 electrode significantly.

Significant effect of electron transfer between current collector and active material on high rate performance of Li_4Ti_5O_(12)

The rate and cycling performances of the electrode materials are affected by many factors in a practical complicated electrode process. Learning about the limiting step in a practical electrochemical reaction is very important to effectively improve the electrochemical performances of the electrode materials. Li4Ti5O12, as a zero-strain material, has been considered as a promising anode material for long life Li-ion batteries. In this study, our results show that the Li4Ti5O12 pasted on Cu or graphite felt current collector exhibits unexpectedly higher rate performance than on A1 current collector. For Li4Ti5O12, the electron transfer between current collector and active material is the critical factor that affects its rate and cycling performances.