【编辑推荐】2024年3期技术交流

12个月前 (09-23) 阅读数 160 #科技

技术交流

卢兵荣^∗ ,陈莉,韩丽华,路遥

(合肥国轩高科动力能源有限公司,安徽合肥 230011)

摘要：通过优化快充电流改善锂离子电池的快充循环寿命。为找到可快速准确得到锂离子电池快充电流的方法，基于单层三电极软包装电池，在25 ℃、35 ℃和45 ℃下进行恒电位测试，得到相应温度下的快充电流。结合大容量电池的仿真温升数据，通过温度电流和荷电状态（SOC）的匹配关系，得到大容量电池对应温度和荷电状态（SOC）下的快充电流，如图1所示。使用该方法得到的快充电流进行快充循环性能测试，结果如图2所示。将该方法得到的快充电流与仿真快充电流进行循环数据对比，发现循环性能提升了6.93倍。对比前期基于伪二维（P2D）模型计算的仿真快充电流，实验得到的快充电流更能反映电池的真实快充能力，充分发挥电芯的快充性能。该方法也可为评测电池负极的快充能力提供理论指导。针对不同负极材料，可制作小软包装电池，进行恒电位测试，得到不同温度下的最大充电倍率。未来可进一步选用合适的负极材料进行快充型电池的体系开发。

Non-lithium plating fast charging strategy for three electrode pouch battery

LU Bingrong ^∗ ,CHEN Li,HAN Lihua,LU Yao

(Hefei Gotion High-Tech Power Energy Co.,Ltd.,Hefei,Anhui 230011,China)

Abstract： The fast charge cycle life of Li-ion batteries is improved by optimizing the fast charge profile. In order to find a method that can accurately and quickly obtain the fast charge current of Li-ion battery, based on the production of a single-layer three electrodes pouch battery, the constant potential tests are conducted at 25 ℃, 35 ℃, and 45 ℃ to obtain the fast charge current at the corresponding temperature. Based on the simulated temperature rise data of a high-capacity battery, the matched relationship between temperature, current, and state of charge (SOC)， the fast charge current corresponding to the temperature and SOC of the high-capacity battery can be obtained, as shown in Fig.1. The fast charging current obtained by this method is used for fast charging cycle performance testing, as shown in Fig.2. By comparing the cycle data of the fast charging current obtained by this method with the simulated fast charging current, it is found that the cycle performance is improved by 6.93 times. Compared with the simulation fast charging current calculated based on the pseudo-two-dimensional(P2D) model in the early stage, the fast-charging current obtained from the experiment can better reflect the true fast charging capacity of the battery and fully leverage the fast charging performance of the battery cell. This method can also provide theoretical guidance for evaluating the fast-charging capacity of battery anodes. For different anode materials, small pouch batteries can be made and subjected to constant potential testing to obtain the maximum charging rate at different temperatures. In the future, suitable anode materials can be further selected for the development of fast-charging battery systems.

引用格式

卢兵荣,陈莉,韩丽华,等. 三电极软包装电池无析锂快充策略[J]. 电池,2024,54(3):344-347.
LU B R,CHEN L,HAN L H,et al. Non-lithium plating fast charging strategy for three electrode pouch battery[J]. Dianchi(Battery Bimonthly),2024,54(3):344-347.（点此下载文章全文）

曹米红¹,张骞^1,2,李路成¹ ,陈军¹^∗

(1. 江西理工大学材料科学与工程学院,江西省动力电池及其材料重点实验室,江西赣州 341000; 2. 江西理工大学宜春江理锂电新能源产业研究院,江西宜春 336023)

摘要：为解决乙炔黑单一导电剂自身团聚的问题，采用含有碳纳米管（CNT）的导电浆料对乙炔黑导电剂进行改性。CNT与乙炔黑复合后，直径为80~100 nm的球形乙炔黑颗粒均匀地分散在直径为20 nm的CNT表面，较好地提高了导电剂的比表面积。结果表明，使用1.5% CNT/乙炔黑复合导电剂的电池的电化学阻抗值较小，使LiNi_0.5Co_0.2Mn_0.3O₂正极材料锂离子电池的综合性能得到显著改善。CNT/乙炔黑电池具有较大的CV曲线面积，氧化峰和还原峰之间的电位差较小。此外，以200 mA/g在2.75~4.20 V循环，CNT/乙炔黑电池的首次充放电比容量分别为151.8 mAh/g和155.5 mAh/g，首次库仑效率为97.6%，远高于原始乙炔黑电池的（分别为148.9 mAh/g、164.0 mAh/g、90.8%）。200次循环后，CNT/乙炔黑电池的放电比容量仍保持在141.9 mAh/g，容量保持率为92.4%，也远高于原始乙炔黑电池的（分别为80.0 mAh/g、51.8%）。此外，在0.2 C、0.5 C、1.0 C、2.0 C、3.0 C和5.0 C的不同倍率下，CNT/乙炔黑复合导电剂电池的放电比容量分别为150.4 mAh/g、145.1 mAh/g、140.1 mAh/g、134.2 mAh/g、128.0 mAh/g和116.9 mAh/g，明显高于乙炔黑单一导电剂电池的（分别为139.2 mAh/g、129.6 mAh/g、121.8 mAh/g、112.6 mAh/g、104.3 mAh/g和87.5 mAh/g），展现出更优越的倍率性能。将乙炔黑与CNT纳米纤维复合之后，较好地提高了LiNi_0.5Co_0.2Mn_0.3O₂电极的放电比容量、首次库仑效率、循环稳定性和倍率性能，为开发新型锂离子电池高性能正极材料用导电剂提供了的改性思路。

Effects of CNT/ acetylene black composite conductive agent
on LiNi _{0. 5}Co_{0. 2}Mn_{0. 3}O₂

CAO Mihong ¹ ,ZHANG Qian ^1,2 ,LI Lucheng ¹ ,CHEN Jun ¹^∗

(1. Jiangxi Key Laboratory of Power Batteries and Materials,Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Sciences and Technology,Ganzhou,Jiangxi 341000,China; 2. Yichun Lithium New Energy Industry Research Institute, Jiangxi University of Science and Technology,Yichun,Jiangxi 336023,China)

Abstract： In order to solve the problem of self-agglomeration of the acetylene black single conductive agent, a conductive slurry containing carbon nanotubes(CNT) is used to modify the acetylene black conductive agent. After recombining CNT with acetylene black, spherical acetylene black particles with a diameter of 80-100 nm are evenly dispersed on the surface of CNT with a diameter of 20 nm, which effectively improves the specific surface area of the conductive agent. The results show that the electrochemical impedance value of the batteries using 1.5% CNT/acetylene black composite conductive agent is smaller, which significantly improves the comprehensive performance of the LiNi_0.5Co_0.2Mn_0.3O₂ cathode material Li-ion battery. The CNT/acetylene black battery has a smaller potential difference between the oxidation peak and the reduction peak. In addition, the initial specific charge/discharge capacities of the CNT/acetylene black battery are 151.8 mAh/g and 155.5 mAh/g respectively with the initial Coulombic efficiency of 97.6%, which are much higher than that of the pristine acetylene black battery (148.9 mAh/g, 164.0 mAh/g, 90.8%). After 200 cycles, the specific discharge capacity of the CNT/acetylene black battery can still be maintained at 141.9 mAh/g with a capacity retention rate of 92.4%, which is much higher than the pristine acetylene black battery (80.0 mAh/g, 51.8%). In addition, the specific discharge capacities at 0.2 C, 0.5 C, 1.0 C, 2.0 C, 3.0 C and 5.0 C are 150.4 mAh/g, 145.1 mAh/g, 140.1 mAh/g, 134.2 mAh/g, 128.0 mAh/g and 116.9 mAh/g, respectively, which are significantly higher than the acetylene black single conductive agent batteries (139.2 mAh/g, 129.6 mAh/g, 121.8 mAh/g, 112.6 mAh/g, 104.3 mAh/g and 87.5 mAh/g, respectively). After recombining acetylene black with CNT nanowires, the specific discharge capacity, initial Coulombic efficiency, cycle stability and rate capability of LiNi_0.5Co_0.2Mn_0.3O₂ electrode are effectively improved, which will provide a modification idea for the development of new conductive agent for high-performance cathode materials of Li-ion batteries.

图1 两种导电剂电池循环200次后的阻抗曲线

Fig.1 Impedance curves of two conductive agent batteries after 200 cycles

图2 两种导电剂电池第4次循环的CV曲线

Fig.2 CV curves of two conductive agent batteries at the fourth cycle

图3 两种导电剂电池的电化学性能

Fig.3 Electrochemical performance of two conductive agent batteries

引用格式

曹米红,张骞,李路成,等. CNT/ 乙炔黑复合导电剂对LiNi_0.5Co_0.2Mn_0.3O₂ 的影响[J]. 电池,2024,54(3):348-353.
CAO M H,ZHANG Q,LI L C,et al. Effects of CNT/ acetylene black composite conductive agent on LiNi_0.5Co_0.2Mn_0.3O₂[J].Dianchi(Battery Bimonthly),2024,54(3):348-353.（点此下载文章全文）

李琼^∗,王治安,朱利民,陈慧,顾秋月

(中国轻工业长沙工程有限公司,湖南长沙 410114)

摘要：负极材料是锂离子电池的重要组成部分。目前，石墨负极在锂离子电池市场占有主导地位，然而石墨有限的理论容量和倍率性能限制锂离子电池的继续发展和应用，寻找高容量和高倍率性能的替代负极材料是迫切需求，硬碳是主要的研究方向。在此背景下，本文作者以间苯二酚和甲醛为前驱体，氨水为催化剂，通过水热法制备酚醛树脂基硬碳材料。采用SEM、高分辨透射电子显微镜（TEM）、X射线衍射（XRD）及N₂吸-脱附测试等对硬碳材料的形貌和结构进行分析，并以金属锂片为对电极制备扣式电池，测试电化学性能。合成的酚醛树脂基硬碳材料具有较大的层间距，其储锂性能和倍率性能也相应提高，同时，电化学性能表现为典型的双电层电容和充放电可逆性。制备的电池以50 mA/g电流在0.01~3.00 V充放电，首次放电比容量达到311.22 mAh/g，首次库仑效率为60.07%；循环50次后，容量保持率为75.7%，表现出良好的循环稳定性和倍率性能。

Performance of phenolic resin-based hard carbon anode material

LI Qiong ^∗ ,WANG Zhian,ZHU Limin,CHEN Hui,GU Qiuyue

(China CEC Engineering Corporation,Changsha,Hunan 410114,China)

Abstract: Anode materials are an important part of Li-ion batteries. At present, graphite anode occupies a dominant position in the Li-ion battery market. However, the limited theoretical capacity and rate capability of graphite limits the continued development and application of Li-ion batteries. It is urgent to seek alternative anode materials with high capacity and rate capability, and hard carbon is the main research direction. On this background, a hydrothermal approach for phenolic resin hard carbon with resorcinol and formaldehyde as precursors and ammonia as catalysts is presented. SEM, high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and N₂ adsorption-desorption tests are adopted to analyze the surface morphology and structural features of the hard carbon materials. The electrochemical performance of the button battery is tested by using lithium metal as the counter electrode. The synthesized phenolic resin-based hard carbon material has increased interlayer spacing, and its lithium storage performance and rate capability are also improved, meanwhile, the electrochemical performance exhibits typical double-layer capacitance and reversibility of charge and discharge. When the prepared battery is charged and discharged at a current of 50 mA/g in 0.01-3.00 V, the initial specific discharge capacity reaches 311.22 mAh/g, and the initial Coulombic efficiency is 60.07%. The capacity retention rate is 75.7% after 50 cycles, which presents satisfactory cyclic stability and rate capacity.

引用格式

李琼,王治安,朱利民,等. 酚醛树脂基硬碳负极材料的性能[J]. 电池,2024,54(3):354-357.
LI Q,WANG Z A,ZHU L M,et al. Performance of phenolic resin-based hard carbon anode material[J]. Dianchi(Battery Bimonthly),2024,54(3):354-357.（点此下载文章全文）

何涛^1,2,张成娟^1,2^∗,雷卓^1,2,王正家^1,2

(1. 湖北工业大学机械工程学院,湖北
武汉 430068; 2. 现代制造工程湖北省重点实验室,湖北武汉 430068)

摘要：软包装锂离子电池是电子产品的重要组件，在生产和运输的过程中，其表面易受外力作用产生凹坑缺陷，影响产品的使用安全。目前，仍主要采用人工检测的方法对凹坑缺陷进行检测，这种检测方法工作强度大，检测精度低且成本高。传统机器视觉方法具有检测效率高和检测成本低的优点，但由于凹坑缺陷对比度低、缺陷区域过小且存在反光，使得传统机器视觉方法很难进行准确检测。因此，本文作者提出了一种基于图像增强和改进DeepLabV3网络的软包装锂离子电池表面凹坑缺陷检测方法。首先，分析了表面凹坑缺陷图像特征，采用中值滤波对凹坑缺陷图像进行滤波处理以降低噪声的影响，并使用直方图均衡化增强凹坑缺陷的对比度。然后，对DeepLabV3网络进行改进，使用ResNet101作为特征提取网络，同时引入位置注意力模块，使得模型更加关注于凹坑缺陷相关特征，提升网络的特征表达能力。最后，分别使用改进前后的DeepLabV3在原始数据集和图像增强后的数据集上进行检测实验，验证了图像增强和改进DeepLabV3的有效性；通过对比不同检测算法对凹坑缺陷的分割效果，验证了改进DeepLabV3对凹坑缺陷的分割性能；对比不同检测算法的检测结果，验证了改进DeepLabV3相比其他算法具有更高的检测准确率。改进后的网络在自制数据集上的平均交并比达到85.98%，缺陷检测准确率达到98.33%。实验结果表明，该方法可以较好实现对软包装锂离子电池表面凹坑缺陷的检测。

Surface pit defects detecting method of pouch Li-ion battery

HE Tao ^1,2,ZHANG Chengjuan ^1,2^∗,LEI Zhuo ^1,2 ,WANG Zhengjia ^1,2

(1. School of Mechanical Engineering,Hubei University of Technology,Wuhan,Hubei 430068,China; 2. Hubei Provincial Key Laboratory of Modern Manufacturing Engineering,Wuhan,Hubei 430068,China)

Abstract: Pouch Li-ion battery is an important component of electronic products, in the process of production and transportation, its surface is susceptible to external forces resulting in pit defects, affecting the safety of the product. At present, the pit defects are still mainly detected by manual inspection methods, this inspection method has high work intensity, low detection accuracy, and high cost. The traditional machine vision method has the advantages of high detection efficiency and low detection cost, but due to the low contrast of the pit defects, the defective area is too small and there is reflection, which makes it difficult for the traditional machine vision method to carry out accurate detection. Therefore, a surface pit defect detection method based on image enhancement and an improved DeepLabV3 network for pouch Li-ion batteries is proposed. Firstly, the surface pit defect image features are analyzed, the median filter is used to filter the pit defect image to reduce the influence of noise, and the contrast of the pit defect is enhanced using histogram equalization. Then the DeepLabV3 network is improved by using ResNet101 as the feature extraction network, and the positional attention module is introduced to make the model pay more attention to the features related to the pit defects and improve the feature expression ability of the network. Finally, detection experiments are conducted on the original dataset and the image-enhanced dataset using DeepLabV3 before and after the improvement, respectively, to verify the effectiveness of the image enhancement and the improved DeepLabV3. The segmentation performance of the improved DeepLabV3 for pit defects is verified by comparing the segmentation effect of different detection algorithms on pit defects. By comparing the detection results of different detection algorithms, it is verified that the improved DeepLabV3 has higher detection accuracy than other algorithms. The average intersection ratio of the improved network on the homemade dataset reaches 85.98%, and the defect detection accuracy reaches 98.33%. The experimental results show that the method can better realize the detection of pit defects on the surface of pouch Li-ion batteries.

引用格式

何涛,张成娟,雷卓,等. 软包装锂离子电池表面凹坑缺陷检测方法[J]. 电池,2024,54(3):358-363.
HE T,ZHANG C J, LEI Z, et al. Surface pit defects detecting method of pouch Li-ion battery[J] . Dianchi( Battery Bimonthly),2024,54(3):358-363.（点此下载文章全文）

田文燕^∗ ,班宵汉,刘富亮,陈晓涛,石斌

(贵州梅岭电源有限公司,特种化学电源全国重点实验室,贵州
遵义 563003)

摘要：负极集流体是锂离子电池的重要组成部分，选择优质集流体可以提高其与活性材料的接触能力，提高活性材料与电解液接触的活性点等，有助于降低电池的内阻，提高电池的倍率和循环等性能。常规的光滑铜箔集流体存在与活性材料粘结不牢固、电化学阻抗大等问题，在反复充放电过程中容易造成活性物质的脱落，导致电池的电化学性能差。与常规铜箔相比，多孔铜箔可以改善活性材料与铜箔之间的界面结合效果，提高活性材料的利用率和电池的循环稳定性。对应用常规铜箔和多孔铜箔作为集流体的锂离子电池，通过SEM、极片电阻仪、接触角测试仪和恒流充放电等方法研究了铜箔带孔之后对电池容量、倍率性能及循环性能的影响。与常规铜箔相比，以多孔铜箔作为集流体制备的极片具有更低的电阻率和更佳的电解液浸润效果，制备的扣式半电池以0.1C充电至2.5 V循环3次进行化成后，首次充放电比容量分别提高了149.50 mAh/g和207.03 mAh/g（见图1）；在10.0C倍率下的平均放电比容量达127.21 mAh/g，较常规铜箔提升了46.28%；以1.0 C在0.001~ 2.500 V循环200次后，电池的容量保持率达52.85%，材料的倍率性能和循环稳定性得到明显提升。

Effect of porous copper foils on the electrochemical performance of hard carbon anodes

TIAN Wenyan^∗ ,BAN Xiaohan,LIU Fuliang,CHEN Xiaotao,SHI Bin

(National Key Laboratory of Advanced Chemical Power Sources,Guizhou Meiling Power Sources Co.,Ltd.,Zunyi,Guizhou 563003,China)

Abstract：The anode collector is an important part of Li-ion battery, and the selection of a high-quality collector can improve its contact ability with active material, increase the active point of contact between active material and electrolyte, which helps to reduce the internal resistance and improve the rate capability and cycle performances of the battery. Conventional smooth copper foil collectors have problems such as weak bonding with active materials and high electrochemical impedance, which can easily cause active materials to fall off during repeated charging and discharging, resulting in poor electrochemical performance of the battery. Compared with conventional copper foils, porous copper foils can improve the interfacial bonding effect between active materials and copper foils, and increase the utilization rate of active materials and the cycling stability of batteries. For Li-ion batteries with conventional copper foil and porous copper foil as the collector, the effects of copper foil with holes on the battery capacity, rate capability and cycle performance are investigated by SEM, electrode resistivity tester, contact angle tester and galvanostatic charge-discharge. Compared with the conventional copper foil, the electrode prepared with porous copper foil as the collector has a lower resistivity and a better electrolyte wetting effect. After being formatted by charging to 2.5 V with 0.1 C and cycled for 3 times, the initial charge-discharge specific capacity of the prepared half battery increases 149.50 mAh/g and 207.03 mAh/g (as shown in Fig.1), respectively. The average specific discharge capacity reaches 127.21 mAh/g at a rate of 10.0 C, improving 46.28% compared to the battery prepared with conventional copper foil. After 200 cycles in 0.001-2.500 V at 1.0 C, the capacity retention rate of the battery increases to 52.85%, and the rate capability and cycle stability of the material have been significantly improved.

图1 CT-HC和WT-HC的首次充放电曲线

Fig.1 Initial charge-discharge curves of CT-HC and WT-HC

引用格式

田文燕,班宵汉,刘富亮,等. 多孔铜箔对硬碳负极电化学性能的影响[J]. 电池,2024,54(3):364-368.
TIAN W Y,BAN X H,LIU F L,et al. Effect of porous copper foils on the electrochemical performance of hard carbon anodes[J]. Dianchi(Battery Bimonthly),2024,54(3):364-368.（点此下载文章全文）

张长安,杨丽杰^∗,曹新龙,贾彦龙

(西安陕煤泾久新能源科技有限公司,陕西西安 713700)

摘要：生物质碳具有独特的孔结构，较大的层间距，可加速Li⁺在无定形碳中的扩散速度。采用纳米硅、沥青、生物质碳，通过喷雾造粒、高温热解法制备生物质碳-硅复合负极材料。通过XRD、SEM、表面分析研究材料的表面形貌特征；通过恒流充放电等实验研究电化学性能。该材料制备扣式电池的首次充电比容量达到1 692.5 mAh/g，首次库仑效率为90.7%。制备的18650型电池在2.75~4.20 V循环，以1.00 C循环616次的容量保持率为91.44%；以0.50 C充电、1.00 C放电循环447次的容量保持率为94.48%。相比于沥青碳-硅复合材料，以0.50 C充电、1.00 C放电，循环398次的容量保持率为91.98%，以1.00 C循环616次的容量保持率仅为84.90%。所制备的生物质碳材料在0.20 C、0.40 C、0.80 C、1.60 C和3.20 C倍率下的比容量分别为344.4 mAh/g、284.5 mAh/g、211.7 mAh/g、172.4 mAh/g和138.6 mAh/g；沥青碳材料在相同倍率下的比容量分别为240.4 mAh/g、190.3 mAh/g、165.3 mAh/g、130.3 mAh/g和90.5 mAh/g。再次以0.10 C倍率循环时，生物质碳材料的比容量为370.6 mAh/g，与首次循环相比，容量保持率为86.2%；沥青碳材料的比容量为210.3 mAh/g，容量保持率为74.1%。在经历了高倍率循环后，生物质碳材料容量保持率较高，说明倍率性能较好。

Electrochemical performance of biomass carbon-silicon composite anode materials

ZHANG Chang’an,YANG Lijie ^∗ ,CAO Xinlong,JIA Yanlong

(Xi’an Shaanxi Coal Keenjion New Energy Technology Co.,Ltd.,Xi’an,Shaanxi 713700,China)

Abstract: Biomass carbon has a unique pore structure and large interlayer space, which can accelerate the diffusion of Li+ in amorphous carbon. Nano-silicon, pitch and biomass carbon are used to prepare biomass carbon-silicon composite anode materials by spray granulation and high-temperature pyrolysis. The surface morphology of materials is studied by XRD, SEM and surface analysis. The electrochemical performance is investigated by galvanostatic charge-discharge experiments. The initial specific charge capacity of the button cell prepared by this material is 1 692. 5 mAh/g and the initial Coulombic efficiency is 90.7%. The prepared 18650 type battery cycles at 2.75-4.20 V, the capacity retention rate of 616 cycles at 1.00 C is 91.44%, 447 cycles at 0.50 C charge, and 1.00 C discharge is 94.48%. Compared with the asphalt carbon-silicon composite, the capacity retention rate of 398 cycles at 0.50 C charge and 1.00 C discharge is 91.98%, and 616 cycles at 1.00 C are only 84.90%. The specific capacity of the prepared biomass carbon materials at 0.20 C, 0.40 C, 0.80 C, 1.60 C, and 3.20 C rates is 344.4 mAh/g, 284.5 mAh/g, 211.7 mAh/g, 172.4 mAh/g, and 138.6 mAh/g, respectively. The specific capacity of bituminous carbon materials at the same magnification rate is 240.4 mAh/g, 190.3 mAh/g, 165.3 mAh/g, 130.3 mAh/g, and 90.5 mAh/g, respectively. The specific capacity of biomass carbon materials is 370.6 mAh/g when the cycle rate is 0.10 C again, and the capacity retention rate is 86.2% compared with the initial cycle. The specific capacity of asphalt carbon materials is 210.3 mAh/g, and the capacity retention rate is 74.1%. After the high-rate cycle, the capacity retention rate of biomass carbon materials is higher, indicating that the rate capability is good.

图1 生物质碳和沥青碳的倍率性能

Fig.1 Rate capability of biomass carbon and pitch carbon

图2 18650型电池的循环性能

Fig.2 Cycle performance of 18650 type battery

引用格式

张长安,杨丽杰,曹新龙,等. 生物质碳-硅复合负极材料的电化学性能[J]. 电池,2024,54(3):369-373.
ZHANG C A, YANG L J, CAO X L, et al. Electrochemical performance of biomass carbon-silicon composite anode materials[J]. Dianchi(Battery Bimonthly),2024,54(3):369-373.（点此下载文章全文）

李艳红,王盈来^∗,屠芳芳,相佳媛

(杭州南都动力科技有限公司,浙江杭州 310000)

摘要：研究测试了数据中心用磷酸铁锂/石墨锂离子电池在有无预紧力下过放电的性能表现，研究对象见表1。该电池具有倍率长循环特性，可进行5.00 C持续放电2 000次。通过对电池进行0~3.65 V、0.20~3.65 V、0.50~3.65 V、0.80~3.65 V和1.50~3.65 V等5个过放电电压区间的循环测试，发现：随着放电截止电压降低，电池的循环衰减逐渐加快，其循环性能见图1。加夹具可提升同一循环区间下的电池寿命，通过电化学阻抗谱（EIS，见图2）和SEM、XRD测试发现，有夹具电池的界面阻抗和电荷转移阻抗更小，外部压力可减少电极界面空隙，增加界面接触面积，抑制电池产气带来的Li⁺活性损失，提升电池的循环性能。无夹具电池的负极材料在充放电过程中，会发生微观变化，导致循环衰减更严重。此外，电池即使在过低的电压下储存，也不会出现容量的衰减。

Effect of overdischarge on Li-ion battery performance under a fixed preload force

LI Yanhong,WANG Yinglai ^∗ ,TU Fangfang,XIANG Jiayuan

(Hangzhou Narada Motive Power Science & Technology Co.,Ltd.,Hangzhou,Zhejiang 310000,China)

Abstract: The performance of lithium iron phosphate/graphite Li-ion batteries used in data centers under overdischarge conditions is evaluated, both with and without preload force. The research subjects are shown in Table 1. These batteries exhibit long cycle life characteristics and can sustain 2 000 continuous discharges at 5.00 C. Through cyclic testing in five overdischarge voltage ranges, including 0-3.65 V, 0.20-3.65 V, 0.50-3.65 V, 0.80-3.65 V, and 1.50-3.65 V. It is observed that as the discharge cutoff voltage decreases, the cycling attenuation of the battery gradually increases. The cycle performance is shown in Fig.1. The addition of fixtures improved the battery's lifespan within the same cycle interval. Through electrochemical impedance spectroscopy (EIS, as shown in Fig.2), SEM, and XRD testing, it is found that batteries with fixtures have smaller interface impedance and charge transfer impedance. External pressure can reduce electrode interface gaps, increase the interface contact area, suppress Li⁺ activity loss caused by battery gas production, and further improve the cycle performance of the battery. The anode material of unclamped batteries will undergo microscopic changes during the charging and discharging process, leading to more severe cycling attenuation. In addition, batteries do not experience capacity decay even when stored at low voltages.

表1 不同充放电电压区间测试电池初始性能

Table 1 Initial performance of batteries tested in different charging and discharging voltage ranges

编号	电压 / V	是否带夹具	开路电压 / mV	电阻 / mΩ	厚度/ mm
A-0	0~3.65	无	3.282	0.218	36.12
A-1	0~3.65	有	3.284	0.217	36.27
B-0	0.20~3.65	无	3.283	0.217	36.11
B-1	0.20~3.65	有	3.281	0.216	36.31
C-0	0.50~3.65	无	3.282	0.224	36.23
C-1	0.50~3.65	有	3.283	0.214	36.27
D-0	0.80~3.65	无	3.283	0.220	36.22
D-1	0.80~3.65	有	3.284	0.218	36.30
E-0	1.50~3.65	无	3.282	0.223	36.33
E-1	1.50~3.65	有	3.282	0.224	36.19
F-0	2.50~3.65	无	3.282	0.223	36.26
F-1	2.50~3.65	有	3.283	0.224	36.22

图1 不同电压区间循环衰减曲线

Fig.1 Cyclic attenuation curves for different voltage ranges

图2 4组电池的阻抗谱图

Fig.2 Impedance spectra of four battery groups

引用格式

李艳红,王盈来,屠芳芳,等. 一定预紧力下过放电对锂离子电池性能的影响[J]. 电池,2024,54(3):374-378.
LI Y H,WANG Y L,TU F F,et al. Effect of overdischarge on Li-ion battery performance under a fixed preload force[J].Dianchi(Battery Bimonthly),2024,54(3):374-378.（点此下载文章全文）

汤秀芬¹^∗ ,米晨²

(1. 宁夏大学电子与电气工程学院,宁夏银川 750021; 2. 宁夏大学资产与实验室管理处,宁夏银川 750021)

摘要：分析阀控铅酸蓄电池（VRLA）电池充电时遵循马斯定律，提出在充电过程中加入负脉冲放电去极化，减少过电势，既提高电池初始充电可接受电流，又提高充电可接受率的脉冲快速充电方法。制作用于12 V/20 Ah以下VRLA电池的脉冲快速充电电路，通过多次充电实验确定具体的充电阶段和优化的充电参数。

脉冲快速充电方法分两个阶段：恒流充电和脉冲循环快速充电，其示意图如图1所示。

恒流充电：0.2 C恒流充电，可以在较短的时间内充入较多的电量，一旦检测到电池端电压大于设定电压，则该阶段充电结束。

脉冲循环快速充电：经过恒流充电后，电池极化现象明显，转入带负脉冲的脉冲充电方式。前停歇期间，欧姆极化瞬间消失，浓差极化也逐渐部分消失；反向脉冲充电可以基本消除浓差极化，既提高初始充电可接受电流，又提高充电可接受率，实现VRLA电池的快速高效无损充电。

Optimization the fast charging parameters of VRLA battery based on Mas laws

TANG Xiufen ¹^∗ ,MI Chen ²

(1. School of Electronic and Electrical Engineering,Ningxia University,Yinchuan,Ningxia 750021,China; 2. Department of Asset and Laboratory Management,Ningxia University,Yinchuan,Ningxia 750021,China)

Abstract: Based on the analysis of Mas laws, a pulse fast charging method is proposed by adding negative pulse discharge depolarization in the charging process to reduce the overpotential, which not only improves the acceptable current of valve-regulated lead-acid (VRLA) battery but also improves the acceptable rate of charging. The pulse fast charging circuit for VRLA batteries below 12 V/20 Ah is designed and fabricated, and the specific charging stage and optimized charging parameters are determined through multiple charging experiments.

The pulse fast charging method is divided into two stages: constant current charging and pulse cycle fast charging. Its schematic diagram is shown in Fig.1.

Constant current charging: 0.2 C constant current charging can charge more power in a short time, once the voltage at the battery end is greater than the set voltage, the charging stage is over.

Pulse cycle rapid charging: after constant current charging, the polarization phenomenon of the battery is obvious, and the battery turns to the pulse charging mode with a negative pulse. During the previous stop, the Ohm polarization disappears instantly, and the concentration polarization gradually disappears. The reverse pulse charging can basically eliminate the concentration polarization, improve the initial charging acceptable current and charging acceptance rate, and realize the fast and efficient non-destructive charging of VRLA battery.

图1 脉冲快速充电方法示意图

Fig.1 Schematic of the pulse fast charging method

引用格式

汤秀芬,米晨. 基于马斯定律优化VRLA 电池快充参数[J]. 电池,2024,54(3):379-382.
TANG X F,MI C. Optimization the fast charging parameters of VRLA battery based on Mas laws[J] . Dianchi( Battery Bimonthly),2024,54(3):379-382.（点此下载文章全文）

谢伟超¹,朱贤徐²,吴志康³ ,唐朝辉²,李加兴^1,3^∗

(1. 雪天盐业集团股份有限公司,湖南长沙 410114; 2. 湖南美特新材料科技有限公司, 湖南长沙 410200; 3. 湖南省井矿盐工程技术研究中心,湖南长沙 410114)

摘要：O3型层状氧化物正极材料NaNi_1/3Fe_1/3Mn_1/3O₂具备高比容量、成本低和较高循环寿命等特点，是钠离子电池正极材料领域的研究热点。为探究钠源对正极材料电化学性能的影响，以Na₂CO₃、NaOH、NaHCO₃和Na₂SO₄等无机钠盐为钠源，采用高温固相反应制得O3-NaNi_1/3Fe_1/3Mn_1/3O₂（分别记为NFM-Na1、NFM-Na2、NFM-Na3和NFM-Na4），通过SEM、X射线光电子能谱（XPS）、XRD、BET比表面积分析等检测手段分析钠源对O3-NaNi_1/3Fe_1/3Mn_1/3O₂材料形貌、结构和电化学性能的影响。不同钠源制备的材料均为一次颗粒聚集而成的多晶结构，平均二次粒径D₅₀均小于5 μm。以Na₂CO₃作为钠源得到的O3-NaNi_1/3Fe_1/3Mn_1/3O₂材料的电化学性能最佳，组装的扣式电池以0.1 C在2.0~4.0 V充放电，首次放电比容量达141.7 mAh/g、库仑效率为95.4%，以1.0 C循环100次，放电比容量从137.2 mAh/g降低至114.3 mAh/g，容量保持率为83.3%。

根据分析与测试的结果，可揭示Na₂CO₃作为钠源所制备产品性能最佳的原因。基于Na₂CO₃作为钠源得到的正极材料结晶度最高，样品表面一部分的Mn元素呈Mn⁴⁺的形式，通过减轻循环过程中Mn的Jahn-Teller效应，使得晶体结构更稳定。此外，进一步测试了样品在不同扫描速率下的CV曲线，探究其晶体结构中Na⁺的动力学行为，结果表明，结晶度高的材料可为Na⁺提供更有序的扩散通道，使扩散更易进行。综上所述，Na₂CO₃是合成O3-NaNi_1/3Fe_1/3Mn_1/3O₂正极材料的优质钠源。

Effects of inorganic sodium sources on
the performance of O3-NaNi _{1 / 3}Fe_{1 / 3}Mn_{1 / 3}O₂

XIE Weichao ¹ ,ZHU Xianxu ² ,WU Zhikang³ ,TANG Zhaohui² ,LI Jiaxing ^1,3^∗

(1. Snowsky Salt Industry Group Co.,Ltd.,Changsha,Hunan 410114,China; 2. Hunan Meite New Material Technology Co.,Ltd., Changsha,Hunan 410200,China; 3. Hunan Well Salt Engineering Technology Research Center,Changsha,Hunan 410114,China)

Abstract: With the characteristics of high specific capacity, low cost, and long cycle life, O3-NaNi_1/3Fe_1/3Mn_1/3O₂ has become a hot research spot in the field of sodium layered oxide cathode material. In order to explore the influence of different sodium sources on the electrochemical performance of cathode materials, a series of O3-NaNi_1/3Fe_1/3Mn_1/3O₂ are obtained by high-temperature solid-state reactions with four common inorganic sodium salts such asNa₂CO₃, NaOH, NaHCO₃, and Na₂SO₄ as sodium sources respectively (marked respectively as NFM-Na1, NFM-Na2, NFM-Na3, and NFM-Na4). SEM, X-ray photoelectron spectroscopy (XPS), XRD, and BET specific surface area analysis are employed to characterize the influence of sodium source on morphology, structure, and electrochemical performance of the O3-NaNi_1/3Fe_1/3Mn_1/3O₂. It is found that the materials prepared by different sodium sources are polycrystalline structures formed by primary particle aggregation, and the average secondary particle size of D₅₀ is less than 5 μm. The O3-NaNi_1/3Fe_1/3Mn_1/3O₂ which used Na₂CO₃ as a sodium source has the best electrochemical performance, the button battery is charged and discharged at 0.1 C in 2.0-4.0 V with the initial discharge capacity reaches 141.7 mAh/g, the initial Coulombic efficiency is 95.4%. When the current rate is 1.0 C, the discharge capacity decreases from 137.2 mAh/g to 114.3 mAh/g after 100 cycles, and the capacity retention is 83.3%.

Based on the results of analysis and testing, the reason why the product prepared using Na₂CO₃ as the sodium source exhibits the best performance is revealed. The cathode material prepared with Na₂CO₃ as the sodium source has the highest crystallinity, and a part of the Mn elements on the sample surface is in the form of Mn⁴⁺, which alleviates the Jahn-Teller effect of Mn during cycling, making the crystal structure more stable. Additionally, the CV curves of the samples at different scan rates to investigate the kinetic behavior of Na⁺ in the crystal structure are tested. The results show that the highly crystalline material can provide more ordered diffusion channels for Na⁺, making the diffusion behavior easier. In summary, Na₂CO₃ is an excellent sodium source for synthesizing O3-NaNi_1/3Fe_1/3Mn_1/3O₂ cathode material.

引用格式

谢伟超,朱贤徐,吴志康,等. 无机钠源对O3-NaNi_1/3Fe_1/3Mn_1/3O₂ 性能的影响[J]. 电池,2024,54(3):383-389.
XIE W C,ZHU X X,WU Z K,et al. Effects of inorganic sodium sources on the performance of O3-NaNi_1/3Fe_1/3Mn_1/3O₂ [J]. Dianchi(Battery Bimonthly),2024,54(3):383-389.（点此下载文章全文）

葛春平¹,李育林² ,薛渭萍³^∗ ,刘康³ ,黄美华⁴

(1. 渭南师范学院物理与电气工程学院,陕西渭南 714000; 2. 深圳日联科技有限公司,广东深圳 518132; 3. 渭南市中心医院 CT 室,陕西渭南 714000; 4. 湘潭大学化学学院,湖南湘潭 411105)

摘要：分析了锂离子电池X射线检测行业目前所普遍使用的传统2维（2D）检测方式存在以下3个方面的问题：（1）X射线锥形投影，不在X射线光路中心的电极存在3维（3D）投影到2D的影像重叠问题，导致边缘电极无法正确测量电池包覆量或极片缺层、多层的问题；（2）行业现行的2D测量方式以45°方向测量正负极片顶端距离d，该距离无法表示或准确换算为极片在x、y两个方向的包覆量；（3）受叠片电池切角工艺影响，2D成像无法清晰的表现出正负极顶端位置，出现多层重影。这3个方面的问题导致叠片式锂离子电池2D检测方式容易出现图1所示的边缘电极重叠问题。

分析了计算机断层扫描（CT）技术在解决叠片式锂离子电池传统2D检测方面的优势。介绍了3种常用的CT成像方式（锥束CT、扇束CT和平行面CT等）以及在不同的检测需求下的选择依据。提出了一种快速CT定向重建技术，通过2D定位切片位置，重建3D体素数据的两张x、y方向切片图像后，再进行正负极顶点定位，实现对包覆量的直接精确计算。如图2所示，通过图2(b)所示2D投影图定位后，同时切出如图2(c)和图2(d)所示的x、y两个方向的图像。

最后，统计了使用所提方法实现的深圳产锂离子电池快速CT检测设备的系统参数及综合产能，同时也比较了该设备和使用传统2D检测方式的深圳产锂离子电池离线检测机在对同一批样本电池测试的误判率和漏判率。结果表明，使用3D检测方式的设备比传统2D检测方式在不增加漏判的情况下，误判率可降低2~3个百分点。

On-line rapid CT detection technology for laminated Li-ion battery

GE Chunping ¹ ,LI Yulin ² ,XUE Weiping ³^∗ ,LIU Kang ³,HUANG Meihua ⁴

(1. School of Physics and Electrical Engineering,Weinan Normal University,Weinan,Shaanxi 714000,China; 2. Shenzhen Unicomp Technology Co.,Ltd.,Shenzhen,Guangdong 518132,China; 3. CT Room of Weinan Central Hospital, Weinan,Shaanxi 714000,China; 4. College of Chemistry,Xiangtan University,Xiangtan,Hunan 411105,China)

Abstracts: The following three problems are analyzed in the traditional two-dimensional (2D) detection method currently commonly used in the Li-ion battery X-ray detection industry: (1) X-ray cone projection: electrodes that are not in the center of the X-ray optical path have overlapping images from three-dimensional(3D) projection to 2D, which leads to the inability to correctly measure the battery coating amount or the problem of missing or multi-layered electrode sheets at the edge electrodes; (2) The current 2D measurement method in the industry measures the distance d between the top of the cathode and anode electrode sheets at a 45° direction. This distance cannot be expressed or accurately converted into the coating amount of the electrode sheets in the x and y directions; (3) Affected by the cutting process of the stacked battery, the 2D imaging cannot clearly show the top position of the cathode and anode electrodes, and multiple layers of ghosting appear. These three problems make the 2D detection method of stacked Li-ion batteries prone to the edge electrode overlap problem shown in Fig.1.

The advantages of computed tomography (CT) technology in solving the traditional 2D detection of stacked Li-ion batteries are analyzed. Three commonly used CT imaging methods (cone beam CT, fan beam CT, and parallel plane CT) are introduced, as well as the basis for selection under different detection requirements. A fast CT directional reconstruction technology is proposed. By 2D positioning of the slice position, two x and y direction slice images of the 3D voxel data are reconstructed, and then the cathode and anode pole vertices are located, so as to realize the direct and accurate calculation of the coating amount. As shown in Fig.2, after positioning by the 2D projection map shown in Fig.2(b), the images in the x and y directions shown in Figure 2 (c) and Fig.2(d) are cut out at the same time.

Finally, the system parameters and comprehensive capacity of the Li-ion battery rapid CT detection equipment which is made in Shenzhen and implemented using the method proposed are counted, and the misjudged rate and missed rate of the equipment and the Li-ion battery offline detection machine which is made in Shenzhen using the traditional 2D detection method are compared in the same batch of sample battery tests. The results show that the equipment using the 3D detection method can reduce the misjudged rate by 2-3 percentage points without increasing the missed rate compared with the traditional 2D detection method.

图1 叠片电池2D成像时的边缘电极重叠

Fig.1 Edge electrode overlap during two-dimensional (2D) imaging of laminated battery

(a)2D投影图像

(b)x、y方向切层位置

(c)x方向CT切层图像

(b)y方向CT切层图像

图2 同一电芯2D投影图与x、y方向CT切层图

Fig.2 2D projection and x, y direction CT slices of the same battery cell

引用格式

葛春平,李育林,薛渭萍,等. 叠片式锂离子电池在线快速CT检测技术[J]. 电池,2024,54(3):390-394.
GE C P,LI Y L,XUE W P,et al. On-line rapid CT detection technology for laminated Li-ion battery[J]. Dianchi(Battery Bimonthly),2024,54(3):390-394.（点此下载文章全文）