Thermal safety boundary of lithium-ion battery at different state of charge

Thermal runaway(TR)is a critical issue hindering the large-scale application of lithium-ion batteries(LIBs).Understanding the thermal safety behavior of LIBs at the cell and module level under different state of charges(SOCs)has significant implications for reinforcing the thermal safety design of the lithium-ion battery module.This study first investigates the thermal safety boundary(TSB)correspondence at the cells and modules level under the guidance of a newly proposed concept,safe electric quantity boundary(SEQB).A reasonable thermal runaway propagation(TRP)judgment indicator,peak heat transfer power(PHTP),is proposed to predict whether TRP occurs.Moreover,a validated 3D model is used to quantitatively clarify the TSB at different SOCs from the perspective of PHTP,TR trigger temperature,SOC,and the full cycle life.Besides,three different TRP transfer modes are discovered.The interconversion relationship of three different TRP modes is investigated from the perspective of PHTP.This paper explores the TSB of LIBs under different SOCs at both cell and module levels for the first time,which has great significance in guiding the thermal safety design of battery systems.

Research on the impact of high-temperature aging on the thermal safety of lithium-ion batteries

Understanding the thermal safety evolution of lithium-ion batteries during high-temperature usage conditions bears significant implications for enhancing the safety management of aging batteries.This work investigates the thermal safety evolution mechanism of lithium-ion batteries during high-temperature aging.Similarities arise in the thermal safety evolution and degradation mechanisms for lithium-ion batteries undergoing cyclic aging and calendar aging.Employing multi-angle characterization analysis,the intricate mechanism governing the thermal safety evolution of lithium-ion batteries during high-temperature aging is clarified.Specifically,lithium plating serves as the pivotal factor contributing to the reduction in the self-heating initial temperature.Additionally,the crystal structure of the cathode induced by the dissolution of transition metals and the reductive gas generated during aging attacking the crystal structure of the cathode lead to a decrease in thermal runaway triggering temperature.Furthermore,the loss of active materials and active lithium during aging contributes to a decline in both the maximum temperature and the maximum temperature rise rate,ultimately indicating a decrease in the thermal hazards of aging batteries.

Analysis on Fracture Mechanics of Unstable Rock

Unstable rock is a kind of global geological disaster with high frequency. This paper, considering three kinds of combined loads which are gravity, fracture water pressure and seismic force, constructs a unstable rock mechanics model and it uses a fracture mechanics method to deduce the composite stress intensity factor of the type I - II. Based on the maximum circumferential stress theory, this article calculates the theo-retical fracture angle by triangle universal formula.

A Comprehensive Approach for the Clustering of Similar-Performance Cells for the Design of a Lithium-Ion Battery Module for Electric Vehicles

An energy-storage system comprised of lithium-ion battery modules is considered to be a core component of new energy vehicles,as it provides the main power source for the transmission system.However,manufacturing defects in battery modules lead to variations in performance among the cells used in series or parallel configuration.This variation results in incomplete charge and discharge of batteries and non-uniform temperature distribution,which further lead to reduction of cycle life and battery capacity over time.To solve this problem,this work uses experimental and numerical methods to conduct a comprehensive investigation on the clustering of battery cells with similar performance in order to produce a battery module with improved electrochemical performance.Experiments were first performed by dismantling battery modules for the measurement of performance parameters.The kmeans clustering and support vector clustering(SVC)algorithms were then employed to produce battery modules composed of 12 cells each.Experimental verification of the results obtained from the clustering analysis was performed by measuring the temperature rise in the cells over a certain period,while air cooling was provided.It was found that the SVC-clustered battery module in Category 3 exhibited the best performance,with a maximum observed temperature of 32℃.By contrast,the maximum observed temperatures of the other battery modules were higher,at 40℃for Category 1(manufacturer),36℃for Category 2(manufacturer),and 35℃for Category 4(k-means-clustered battery module).

A Fast Charging–Cooling Coupled Scheduling Method for a Liquid Cooling-Based Thermal Management System for Lithium-Ion Batteries

Efficient fast-charging technology is necessary for the extension of the driving range of electric vehicles.However,lithium-ion cells generate immense heat at high-current charging rates.In order to address this problem,an efficient fast charging–cooling scheduling method is urgently needed.In this study,a liquid cooling-based thermal management system equipped with mini-channels was designed for the fastcharging process of a lithium-ion battery module.A neural network-based regression model was proposed based on 81 sets of experimental data,which consisted of three sub-models and considered three outputs:maximum temperature,temperature standard deviation,and energy consumption.Each sub-model had a desirable testing accuracy(99.353%,97.332%,and 98.381%)after training.The regression model was employed to predict all three outputs among a full dataset,which combined different charging current rates(0.5C,1C,1.5C,2C,and 2.5C(1C=5 A))at three different charging stages,and a range of coolant rates(0.0006,0.0012,and 0.0018 kg·s^(-1)).An optimal charging–cooling schedule was selected from the predicted dataset and was validated by the experiments.The results indicated that the battery module’s state of charge value increased by 0.5 after 15 min,with an energy consumption lower than 0.02 J.The maximum temperature and temperature standard deviation could be controlled within 33.35 and 0.8C,respectively.The approach described herein can be used by the electric vehicles industry in real fast-charging conditions.Moreover,optimal fast charging-cooling schedule can be predicted based on the experimental data obtained,that in turn,can significantly improve the efficiency of the charging process design as well as control energy consumption during cooling.

Recent advances in Industrial Internet:insights and challenges

The Industrial Internet is a promising technology combining industrial systems with Internet connectivity to significantly improve the product efficiency and reduce production cost by cooperating with intelligent devices,in which the advanced computing,big data analysis and intelligent perception techniques have been involved.This paper comprehensively surveys the recent advances of the Industrial Internet,including reference architectures,key technologies,relative applications and future challenges.Reference architectures which have been proposed for different application scenarios and their corresponding characteristics are summarized.Key technologies,such as cloud computing,mobile edge computing,fog computing,which are classified according to different layers in the architecture,are presented to support a variety of applications in the Industrial Internet.Meanwhile,future challenges and research trends are discussed as well to promote further research of the Industrial Internet.

Improved interfacial property by small molecule ethanediamine for high performance inverted planar perovskite solar cells

We report a simple and effective method to realize desirable interfacial property for inverted planar perovskite solar cells(PSCs)by using small molecule ethanediamine for the construction of a novel polyelectrolyte hole transport material(P3CT-ED HTM).It is found that P3CT-ED can not only improve the hole transport property of P3CT-K but also improve the crystallinity of adjacent perovskite film.In addition,the introduction of ethanediamine into P3CT realigns the conduction and valence bands upwards,passivates surface defects and reduces nonradiative recombination.As a consequence,compared to P3CT-K hole transport layer(HTL)based devices,the average power conversion efficiency(PCE)is boosted from17.2% to 19.6% for the counterparts with P3CT-ED,with simultaneous enhancement in open circuit voltage and fill factor.The resultant device displays a champion PCE of 20.5% with negligible hysteresis.

Relay Beamforming Design for Physical Layer Secure Communication via Line Search Algorithm

This paper considers a physical layer se-curity model in wireless communications.Two legit-imate users communicate through several relays with the presence of an eavesdropper.We jointly design the relay beamforming weights and minimize the to-tal relay transmit power,while ensuring users’Qual-ity of Services and preventing the information being eavesdropped at the same time.The problem is a robust optimization problem,because of the imper-fect channel state information from users and relays to the eavesdropper.First the original problem is sim-plified,where the high order robust terms are omit-ted.Then we design an iterative algorithm based on line search,by solving two Quadratically Con-strained Quadratic Programming subproblems and a one-dimensional subproblem.Simulation results indi-cate that the proposed algorithm outperforms the state of the arts.

Expression profile of circRNA in biliary atresia and choledochal cyst

To the Editor:Biliary atresia(BA)is a rare obliterative cholangiopathy that occurs during infancy in association with destructive liver inflammation and hepatic fibrosis.Although recent studies have shown that transforming growth factor-b(TGF-b)plays an important role in liver fibrosis and inflammation in BA,disease mechanisms remain poorly understood.Circular RNAs(circRNAs)are a recently discovered unique class of regulatory RNA molecules with high specificity.As previous evidence links circRNAs to the regulation of the TGF-b inflammatory signaling pathway,we further investigated the potential regulatory roles of circRNAs in BA and found novel insights into BA pathogenesis.

Implementing the free HPV vaccination for adolescent girls aged below 14 in Shenzhen,Guangdong Province of China:experience,challenges,and lessons

Cervical cancer is a major public health concern in China,accounting for almost one-fifth of the global incidence and mortality.The recently prequalified domestic bivalent human papillomavirus(HPV)vaccine offers a practical and feasible preventive measure.In response to the global call for action,the National Health Commission issued an Action Plan to eliminate cervical cancer by 2030,with promotion of the HPV vaccination for school-aged girls as a critical step.Despite this,implementation of the vaccination has been patchy,with very low coverage among eligible girls.To address this,from December 2021 to December 2022,a demonstration project was launched in Shenzhen,Guangdong Province,to promote the inclusion of HPV vaccine in local immunisation programme and to address existing barriers to implementation.Using multiple sources of data,this article presents a case study of the demonstration project,analysing its impact on rolling out HPV vaccination among eligible girls and identifying any challenges encountered during implementation.The demonstration project has shown promising results in increasing the HPV vaccination rate,promoting public awareness and acceptance of the domestic HPV vaccine,and establishing a model for quickly scaling up the vaccination at the municipal level.The success of the project can be attributed to several factors,including strong governmental commitment,sufficient funding,multi-sectoral collaboration,ensured vaccine accessibility and affordability,improved vaccination services,and effective health education and communication strategies.Lessons learned from Shenzhen can provide valuable insights for future advocacy and implementation of the vaccination in other areas of China,but challenges must be addressed to achieve universal coverage.These include addressing vaccine hesitancy,expanding the programme to cover a broader age range,and ensuring consistent quality of vaccination services in primary care facilities.Overcoming these challenges will require innovative strategies,public-private partnerships,and sustained funding and resources.Future research should focus on evaluating the long-term effectiveness of the vaccination programme and identifying contextual factors that may impact its implementation in different settings.Overall,the effective control of cervical cancer in China will rely on the“political will”to ensure the incorporation of preventive interventions into policies and universal programme coverage.

高稳定性铋基钙钛矿纳米晶的可控合成:结构和光物理性质

铋基钙钛矿因毒性低成为铅基钙钛矿的潜在替代品.目前,对铋基钙钛矿纳米晶的化学组成、晶体结构以及光物理过程的研究还缺乏系统性.特别地,紫外-可见吸收光谱和激发态载流子动力学,在已发表的论文中存在相当大的争议.在本文中,我们通过热注入法成功地合成了纯相的Cs_(3)BiBr_(6)和Cs_(3)Bi_(2)Br_(9)纳米晶,并通过调节热注入的温度来精确控制二者的化学组成和结构.在此基础上,系统研究了不同形貌和不同尺寸的Cs_(3)Bi_(2)Br_(9)纳米晶的紫外-可见吸收光谱,澄清了在这方面存在的争议.采用飞秒瞬态吸收光谱系统研究了Cs_(3)Bi_(2)Br_(9)纳米晶的激发态载流子动力学,结果表明载流子在被激发后的3 ps内会发生一个自捕获过程.与配体辅助再沉积法相比,用热注入法制备的Cs_(3)Bi_(2)Br_(9)纳米晶具有更好的光稳定性.基于Cs_(3)Bi_(2)Br_(9)纳米晶的光电探测器具有灵敏的光响应,显示出其在光电探测方面的应用潜力.

Advanced municipal wastewater treatment and simultaneous energy/resource recovery via photo(electro)catalysis

Wastewater management and energy/resource recycling have been extensively investigated via photo(electro)catalysis.Although both operation processes are driven effectively by the same interfacial charge,each system is practiced separately since they require very different reaction conditions.In this review,we showcase the recent advancements in photo(electro)catalytic process that enables the wastewater treatment and simultaneous energy/resource recovery(WT-ERR).Various literatures based on photo(electro)catalysis for wastewater treatment coupled with CO_(2)conversion,H_(2)production and heavy metal recovery are summarized.Besides,the fundamentals of photo(electro)catalysis and the influencing factors in such synergistic process are also presented.The essential feature of the catalysis lies in effectively utilizing hole oxidation for pollutant degradation and electron reduction for energy/resource recovery.Although in its infancy,the reviewed technology provides new avenue for developing next-generation wastewater treatment process.Moreover,we expect that this review can stimulate intensive researches to rationally design photo(electro)catalytic systems for environmental remediation accompanied with energy and resource recovery.

Stability of potentially toxic elements in municipal sludge biochars modified by MgCl2 and phosphate

Municipal wastewater sludge can be pyrolyzed as biochars to better use nutrients and stabilize carbon compared with other typical technologies,such as landfill and incineration.However,sludge-derived biochars might contain large amounts of potentially toxic elements(PTEs),such as Zn,Cu,Cr,Ni,Pb,and As.The stability of PTEs in biochars might be improved by higher pyrolytic temperatures,which can be further improved by different modifications.Herein,PO4-modification at 300°C and Cl-modification at 700°C were carried out,respectively,to enhance the stability of PTEs.Various leaching tests have been performed to assess the stability of PTEs in biochars,including the synthetic precipitation leaching procedure(SPLP),toxicity characteristic leaching procedure(TCLP),diethylenetriamine pentaacetate(DTPA)extraction,and in vitro simple bioaccessibility extraction test(SBET).The morphological structure,elemental mapping,and mineral formation of the pristine and modified biochars were studied by scanning electron microscopy–energy-dispersive X-ray spectroscopy(SEM–EDS)and X-ray diffraction(XRD).Our results suggested that the leachability,mobility,plant-availability,and bioaccessibility of most PTEs were decreased by pyrolysis,yet the total contents of PTEs were elevated,especially at 700°C.Generally,modification by phosphates and MgCl2 enhanced the stability of PTEs in biochars.Nevertheless,it should be noted that higher bioaccessibility of PTEs was observed in biochars of P-modification than Cl-modification,which is associated with the dissolution of phosphate precipitates under acidic conditions(pH<2).Additionally,Cl-modification leads to higher plant-available Zn and Cu and bioaccessible Zn compared with the unmodified biochar produced at 700°C.

胎儿小脑表面叶裂的产前超声研究

目的研究正常胎儿小脑表面叶裂随孕周的变化规律并建立孕16~32周正常胎儿小脑叶裂数目参考值。方法选取2019年6月至2020年12月在南方医科大学附属深圳妇幼保健院行产前超声检查无结构异常的644名妊娠12~32周的单胎孕妇,按孕周分为2个时间段观察:孕12~15周为阶段1,孕16~32周为阶段2,在二维图像上观察原裂、水平裂的显示情况并计数孕16~32周小脑原裂之前、原裂与水平裂之间、水平裂之后的叶裂数目及总数目,并分析其形态变化。随机抽取40名阶段2胎儿行叶裂数目两测量者间的组内相关系数(ICC)分析;建立阶段2胎儿小脑叶裂数目的参考值范围,采用Spearman相关行叶裂数目与孕周的相关性分析并建立拟合方程。结果叶裂数目的计数两观察者之间的重复性检验一致性较好(ICC=0.969,P<0.001)。各散点图显示正常胎儿小脑原裂之前、原裂与水平裂之间、水平裂之后叶裂数目及总数目与孕周呈正相关(r=0.863、0.698、0.831、0.932,P均<0.001)。建立了各区域叶裂数目及总数目与孕周的二次多项式回归方程,原裂之前、原裂与水平裂之间、水平裂之后叶裂数以及总数目与孕周的回归方程分别为:Y=0.974X-0.014X^(2)-12.65,Y=0.362X-0.005X^(2)-4.843,Y=-0.125X+0.006X^(2)+0.285,Y=1.800X-0.024X^(2)-22.904。结论利用产前超声可以较好地观察胎儿小脑表面叶裂并对其发育情况作出初步评估。胎儿小脑表面叶裂数目的正常参考值以及形态变化规律能为产前超声评估小脑皮质发育作出参考。

All-temperature area battery application mechanism,performance,and

Further applications of electric vehicles(EVs)and energy storage stations are limited because of the thermal sensitivity,volatility,and poor durability of lithium-ion batteries(LIBs),especially given the urgent requirements for all-climate utilization and fast charging.This study comprehensively reviews the thermal characteristics and management of LIBs in an all-temperature area based on the performance,mechanism,and thermal management strategy levels.

Thermal characteristic evolution of lithium-ion batteries during the whole lifecycle

This work extensively investigates the thermal characteristic evolution of lithium-ion batteries under different degradation paths,and the evolution mechanism through multi-angle characterization is revealed.Under different degradation paths,the evolution trend of temperature rise rate remains unchanged with respect to depth of discharge during the adiabatic discharge process,albeit to varying degrees of alteration.The temperature rise rate changes significantly with aging during the adiabatic discharge process under low-temperature cycling and high-rate cycling paths.The total heat generation rate,irreversible heat generation rate,and reversible heat generation rate exhibit similar evolution behavior with aging under different degradation paths.The interval range of endothermic process of reversible electrochemical reactions increases and the contribution of irreversible heat to the total heat increases with aging.To further standardize the assessment of different degradation paths on the thermal characteristics,this work introduces the innovative concept of“Ampere-hour temperature rise”.In low-temperature cycling and high-rate cycling paths,the ampere-hour temperature rise increases significantly with aging,particularly accentuated with higher discharge rates.Conversely,in high-temperature cycling and high-temperature storage paths,the ampere-hour temperature rise remains relatively stable during the initial stages of aging,yet undergoes a notable increase in the later stages of aging.The multi-angle characterization reveals distinct thermal evolution behavior under different degradation paths primarily attributed to different behavior changes of severe side reactions,such as lithium plating.The findings provide crucial insights for the safe utilization and management of lithium–ion batteries throughout the whole lifecycle.

慢病毒载体定量检测方法的研究进展

免疫疗法正在发展成为一种可用于多种恶性肿瘤的有效且侵入性较小的治疗方法。慢病毒载体(Lentiviral vectors,LVs)因其能够稳定地整合相对较大的外源DNA,并且有效地转导分裂细胞和非分裂细胞,已在免疫治疗中显现出巨大潜力。临床应用对慢病毒载体具有较高的质量要求,需要对最终产品进行严格的质量控制以保证其纯度、效力和安全性。其中慢病毒载体的定量检测是产品研发和质控的关键环节之一。文中总结了LVs定量检测的现有方法,包括流式细胞术(Fluorescence activated cell sorter,FACS)、P24酶联免疫法(P24 enzyme-linked immunosorbent assay,P24 ELISA)、实时荧光定量PCR方法 (Real-time fluorescence quantitative polymerase chain reaction,RT-q PCR)、纳米粒子跟踪分析(Nanoparticle tracking analysis,NTA)、可调电阻式脉冲传感(Tunable resistive pulse sensing,TRPS)和病毒计数仪(Virus counter,VC),并对其优缺点进行比较,对发展新的检测方法和存在的挑战进行了展望。

乡村景观生物多样性研究进展

乡村景观是一种人文和自然共生的复合生态系统,为生物多样性的维持提供了支持。目前,中国传统乡村地区生物多样性的维持正面临着农业集约化、人工林树种单一化、非农业用地急剧扩张及生态传承机制解体等复杂多样的威胁,亟待展开深入研究。本文在总结乡村景观生物多样性相关概念及特征的基础上,通过文献分析概括了国际乡村景观生物多样性的热点研究方向,包括农业集约化下的生物多样性管理、区域尺度乡村景观与生物多样性的协同关系、局地尺度不同乡村景观类型的物种多样性及乡村景观中的生物文化多样性,进一步梳理了国内在相关研究方向上的主要进展并指出研究不足。在此基础上提出未来研究展望,包括突出生物文化多样性特征、加强多时空尺度分析、深化动态维持机制研究、推进生物多样性研究在乡村生态景观规划中的全过程应用等建议。

三嗪石墨炔钝化晶界缺陷以提升钙钛矿太阳能电池的性能

钙钛矿晶界处的缺陷是造成非辐射复合和迟滞效应的主要原因.在本工作中,我们将三嗪石墨炔(一种富氮的碳材料)引入到钙钛矿中钝化晶界缺陷.实验结果表明,三嗪石墨炔能够均匀地分散于钙钛矿体相中,并且和晶界处暴露的Pb^2+发生强相互作用,这确保了三嗪石墨炔能够有效地钝化晶界,防止晶界离子迁移.开尔文电镜和荧光分析证明高度共轭的三嗪石墨炔存在于晶界处,有利于载流子的提取和传输.得益于晶界缺陷的钝化和高效的载流子传输,基于三嗪石墨炔的钙钛矿太阳能电池展现了更小的非辐射复合.因此,三嗪石墨炔优化后的MAPbI3器件光电转换效率为20.33%,迟滞效应可以忽略不计.同样地,将三嗪石墨炔的钝化方法拓展至FAPbI3器件中,得到了21.16%的最佳效率.本文展现的三嗪石墨炔钝化晶界缺陷的方法能够有效提升钙钛矿太阳能电池的性能和抑制迟滞效应.

Optimising the electroluminescence performance of ZnS:Cu/epoxy composites via exploring the relationship between electroluminescence intensity and filler intrinsic attributes

Electroluminescent composites have considerable potential for applications in photoelectric display,electric field measurement and other fields due to their advantages of simple preparation and uniform luminescence.However,high voltage required by the operation of electroluminescent composites hinders their applications in the electric domain,and research on the relationship between electroluminescence principle of composites and filler intrinsic attributes is insufficient.In this paper,the effects of electric field strength,filler mass fraction and voltage frequency on the electroluminescence intensity of ZnS:Cu/epoxy composites are studied,which are majorly used as the luminescent layer of electroluminescent devices.To enhance the electroluminescence intensity of composites,high-temperature sintered BaTiO_(3)and zinc oxide whiskers(ZnOw)particles are introduced in the base matrix.The finite element method is applied to verify that the matrix of high dielectric constant is in favour of improving the electroluminescence intensity of composites.The band structure of the ZnS:Cu particle is calculated based on the density functional theory+U method to analyse the intrinsic relationship between electroluminescence and particle electronic structure.This paper provides a basis for the research of high electroluminescence intensity devices and will be conducive to better understanding on the relationship between electroluminescence principle and filler intrinsic attributes.