Three-dimensionalization via control of laser-structuring parameters for high energy and high power lithium-ion battery under various operating con ditions

Laser-structuring is an effective method to promote ion diffusion and improve the performance of lithium-ion battery(LIB)electrodes.In this work,the effects of laser structuring parameters(groove pitch and depth)on the fundamental characteristics of LIB electrode,such as interfacial area,internal resistances,material loss and electrochemical performance,are investigated,LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathodes were structured by a femtosecond laser by varying groove depth and pitch,which resulted in a material loss of 5%-14%and an increase of 140%-260%in the in terfacial area between electrode surface and electrolyte.It is shown that the importance of groove depth and pitch on the electrochemical performance(specific capacity and areal discharge capacity)of laser-structured electrode varies with current rates.Groove pitch is more im porta nt at low current rate but groove depth is at high curre nt rate.From the mapping of lithium concentration within the electrodes of varying groove depth and pitch by laser-induced breakdown spectroscopy,it is verified that the groove functions as a diffusion path for lithium ions.The ionic,electronic,and charge transfer resistances measured with symmetric and half cells showed that these internal resistances are differently affected by laser structuring parameters and the changes in porosity,ionic diffusion and electronic pathways.It is demonstrated that the laser structuring parameters for maximum electrode performance and minimum capacity loss should be determined in consideration of the main operating conditions of LIBs.

Review of high-power pulsed systems at the Institute of High Current Electronics

In this paper,we give a review of some most powerful pulsed systems developed at the Institute of High Current Electronics(HCEI),Siberian Branch,Russian Academy of Sciences,and describe latest achievements of the teams dealing with these installations.Besides the presented high-power systems,HCEI performs numerous investigations using much less powerful generators.For instance,last year much attention was paying to the research and development of the intense low-energy(<200 kV)high-current electron and ion beam and plasma sources,and their application in the technology[1-3].

Energy band adjustment of 808 nm GaAs laser power converters via gradient doping

The gradient doping regions were employed in the emitter layer and the base layer of GaAs based laser power converters(LPCs).Silvaco TCAD was used to numerically simulate the linear gradient doping and exponential gradient doping structure,and analyze the transport process of photogenerated carriers.Energy band adjustment via gradient doping improved the separation and transport efficiency of photogenerated carriers and reduced the total recombination rate of GaAs LPCs.Compared with traditional structure of LPCs,the photoelectric conversion efficiency of LPCs with linear and exponential gradient doping structure were improved from 52.7%to 57.2%and 57.7%,respectively,under 808 nm laser light at the power density of 1 W/cm^(2).

Energy measurement system of a large-aperture high power laser experiment platform

An energy measurement system in a large-aperture high power laser experiment platform is introduced. The entire measurement system includes five calorimeters, which carry out the energy measurement of the fundamental frequency before the frequency conversion unit, remaining fundamental frequency, remaining second-harmonics, third-harmonics,as well as the energy balance measurement after the frequency conversion unit. Combinational indirect calibration and direct calibration are employed to calibrate the sampling coefficients of the calorimeters. The analysis of the data showed that, regarding the energy balance coefficients, combinational calibration approach gives a higher precision, and leads to an energy balance with 1%; and regarding the energy sampling coefficients for the various wavelengths after the frequency conversion, the results from direct and combinational calibration are consistent. The uncertainties for all energy sampling coefficients are within 3%, which guarantees the reliability of the energy measurement for the laser facility.

High-energy and high-peak-power GHz burst-mode all-fiber laser with a uniform envelope and tunable intra-burst pulses

We report a Yb-doped all-fiber laser system generating burst-mode pulses with high energy and high peak power at a GHz intra-burst repetition rate.To acquire the uniform burst envelope,a double-pre-compensation structure with an arbitrary waveform laser diode driver and an acoustic optical modulator is utilized for the first time.The synchronous pumping is utilized for the system to reduce the burst repetition rate to 100 Hz and suppress the amplified spontaneous emission effect.By adjusting the gain of every stage,uniform envelopes with different output energies can be easily obtained.The intra-burst repetition rate can be tuned from 0.5 to 10 GHz actively modulated by an electro-optic modulator.Optimized by timing control of eight channels of analog signal and amplified by seven stages of Yb-doped fiber amplifier,the pulse energy achieves 13.3 mJ at 0.5 ns intra-burst pulse duration,and the maximum peak power reaches approximately3.6 MW at 48 ps intra-burst pulse duration.To the best of our knowledge,for reported burst-mode all-fiber lasers,this is a record for output energy and peak power with nanosecond-level burst duration,and the widest tuning range of the intra-burst repetition rate.In particular,this flexibly tunable burst-mode laser system can be directly applied to generate high-power frequency-tunable microwaves.

考虑条件风险价值和阶梯碳交易的综合能源系统优化调度

为进一步提升综合能源系统环境效益,减少新能源出力不确定性所带来的潜在风险,提出了计及条件风险价值(conditional value at risk,CVaR)以及阶梯碳交易的综合能源系统优化调度模型。考虑到系统风电和光伏出力不确定性可能带来的影响,采用条件风险价值量度不确定性带来的潜在风险,并将碳捕获技术、电转气设备以及阶梯式碳交易机制引入系统调度模型,构建了综合考虑系统运行成本和碳交易成本的优化调度目标函数,由于所建立模型为混合整数规划问题,采用CPLEX求解器进行求解,设置4种场景进行验证分析,算例表明所提模型可有效减少二氧化碳排放,在兼顾经济性和环境性的同时引入CVaR,可避免由于忽略风光不确定性所带来的较为乐观的调度结果,使系统最终调度结果更为合理。

某纯电驱动重载车辆能耗预测模型

高精度能耗预测模型是准确预测车辆续驶里程的重要前提。针对载荷大幅度变化且非结构化道路运行的纯电驱动重载车辆,建立其组合能耗模型,该模型由能耗计算基本模型与长短时记忆(Long Short-Term Memory,LSTM)神经网络差值修正两部分组成。基于能量流动过程驱动电机和变速器效率建模,结合汽车行驶动力学建立能耗计算基本模型;采用LSTM神经网络来修正基本模型能耗预测结果与车辆典型工况功率测试值的差值,有效提高了大幅变载荷且低信噪比坡度环境下的车辆能耗预测精度,因此组合能耗模型具有参数简单和模型拟合不需解释能耗规律的优点。经试验测试分析,与VT-Micro能耗模型和径向基(Radial Basis Function,RBF)神经网络能耗模型相比,所提组合能耗模型的功率预测平均误差率分别降低了17.76%和3.35%,能够实现纯电驱动重载车辆复杂工况下能耗的准确实时预测。

面向电网调峰的盘管式冰蓄冷空调技术研究

储能是助力实现碳达峰碳中和战略目标的关键技术。当前电力供需关系的矛盾随着可再生能源高比例接入和电力需求快速增长日益尖锐,该问题在夏季用电高峰期间尤为突出。冰蓄冷空调系统在夜间利用谷电制冰储存冷量,在白天用电高峰时融冰供冷,有助于电网调峰和改善用能经济性。该文总结分析盘管式冰蓄冷空调关键技术的研究现状和发展方向。系统控制层面:对比分析冰蓄冷空调系统的各种优化控制策略;蓄冰融冰方式层面:详细阐述内融冰、外融冰和内外融冰结合3种方式特点,并对能量模型进行归纳;结构层面:分析典型强化传热方式对传热性能的影响关系。最后,归纳不同材质盘管的研究结果与应用前景。

定向能武器在电磁空间的运用

为探讨以激光武器和高功率微波武器为代表的定向能武器在电磁空间中的作战应用,采用演绎和类比的研究方法,从电磁频谱的物理原理和战争基本规律出发,论述电磁空间的基本性质、电磁火力的基本特点、电磁精确战的基本原理,以及定向能武器的基本定位、优势劣势、软硬杀伤。分析定向能武器在电磁空间的信息破坏力与信息创造力,梳理总结定向能武器的主要作战场景及运用方式,最后就加快定向能武器走向实战提出建议。

空调冷凝器管道激光超声导波跨能量层级映射迁移检测方法

空调冷凝器是空调设备的关键部件,其弯管连接部位由于损伤类型多和几何形状复杂等原因造成传统接触式损伤检测手段难以应用,本文提出一种基于能量映射迁移网络的非接触式激光超声导波无损检测方法。首先,通过小波分解提取烧蚀信号和热弹信号的概貌波形,设计自编码能量映射函数将热弹信号特征空间映射到烧蚀信号特征空间,获得更接近烧蚀信号特征的映射热弹信号。其次,通过能量映射迁移网络对齐映射热弹信号和烧蚀信号特征空间,将网络模型中的域转换误差和样本标签误差之和用作特征空间对齐误差值。最后,对空调冷凝器泄漏、分层和裂纹等损伤进行检测实验验证所提新方法性能,结果表明其损伤识别精度为93.09%,比传统激光热弹激励检测方法提高了7.23%。

计及驾驶风格的氢燃料电池有轨电车自适应能量管理策略

半独立路权运行模式下,氢燃料电池混合动力有轨电车驾驶员的驾驶风格影响锂电池荷电状态,从而对整车运行经济性有较大影响。提出一种结合驾驶员驾驶风格的自适应能量管理策略,以提高能量管理策略对工况和驾驶风格的适应性。首先,考虑不同的道路工况对驾驶员驾驶风格的影响,通过K-均值聚类算法对行驶工况进行识别,将行驶工况分为低速、中速、高速3类;引入冲击度和加速度标准差构建基于模糊逻辑的算法,对驾驶风格进行识别,将驾驶风格分为迟钝型、标准型、激进型3类。其次,建立系统瞬时氢耗量最优的目标函数,在满足约束条件的前提下,引入锂电池荷电状态等效因子修正系数,针对不同驾驶风格调整传统等效氢耗最小策略中相应的等效因子,以实现等效因子随驾驶风格的改变实时变化。最后,将该策略与传统等效氢耗最小策略、庞特里亚金极小值策略进行仿真对比分析,结果表明:该策略能实现3个动力源功率分配最优;锂电池和超级电容荷电状态波动曲线相较于其他2种策略最为平滑;在续驶里程结束时混合动力系统氢耗量为1.39 kg,具有最为优越的燃油经济性;母线电压最大偏移率最小;能使3个动力源平稳出力,具有较强的系统稳定性。研究结果为进一步提高有轨电车实际运行中对驾驶风格的适应性提供参考。

地下车站供冷季用能特征分析与基于需求响应的调峰潜力评估

聚焦地铁车站小时尺度用能特征,以长江中下游地区某典型屏蔽门地下车站为例,分析了车站逐时能耗构成及通风空调系统能耗的影响因素。研究结果表明,通风空调能耗为地铁车站动力照明能耗的最大占比项,占比可达83%,室外空气参数、客流量与发车密度均与通风空调能耗呈现显著相关关系。面向需求响应,建立了混合整数规划模型,评估蓄能参与下的地铁车站调峰潜力。模拟结果表明,蓄能装置参与下,车站全年累计高峰时段用电量可大幅削减,48.2%的高峰时段用电量可转移至平时段和低谷时段。

基于校正条件生成对抗网络的风电场群绿氢储能系统容量配置

以条件生成对抗网络(CGAN)为代表的半监督学习可计及风电波动并生成出力场景集合,生成的数据可输入氢气储能容量配置模型以支撑优化求解。为此,该文首先设计一种校正条件生成对抗网络(CCGAN),并基于风电预测误差构建条件校正器,对预测失准事件和风电爬坡事件下输入生成器的标签信息进行识别和校正;然后,以储能定容的综合成本和各风场弃风成本为目标函数,构建绿氢储能容量配置的多目标优化模型,并引入基于切比雪夫距离的膝区域数学概念,以指导多目标优化算法设计;最后,以新英格兰39节点系统为例进行算例分析,结果表明未经校正的条件信息将导致定容决策偏离实际,而CCGAN能生成计及风电不确定性的高置信出力场景,使得容量配置结果兼顾鲁棒性和经济性。

大功率高能脉冲激光电源设计

根据YAG激光器对大功率高能量脉冲电源的应用需求,设计了一种大功率脉冲激光电源,可实现高脉冲能量重复频率输出及充电电压灵活调控。前级充电网络采用串联LC谐振变换器,后级脉冲形成网络选择晶闸管触发LC放电电路。最终,研制了1台7 kW实验样机,最大重复频率10 Hz,最高充电电压2.2 kV,可实现单脉冲最高700 J电能输出,满足大功率高能脉冲输出的应用需求,实验测试结果验证了设计的可行性。

机载130 mJ激光照射器的脉冲驱动电源设计

针对机载130 mJ激光照射器对脉冲驱动电源的实际使用需求,设计了一款高可靠性、宽温度范围、小型化的脉冲驱动电源。采用了基于超低ESR储能单元的前级低功率充电、后级高功率脉冲放电的技术方案。详细设计中,防反及缓启电路采用双PMOS管的方式;BOOST升压式充电电路选用具有开关频率可调、逐周期电流限制的控制芯片CYT5022JVS;储能单元由多只超低ESR的高分子固态铝电解电容器并联构成;放电电路开关管选用两只2.3 mΩ导通内阻的IRF150P220并联来降低发热功率。为保证宽温工作范围,采用电压补偿的方式来解决高、低温下储能单元容值变化的问题。测试表明,驱动电源能够输出峰值160 A、脉宽230μs、频率25 Hz的脉冲电流,激光照射器在照射模式下单脉冲平均能量大于130 mJ,满足系统要求。

An explainable AI framework for robust and transparent data-driven wind turbine power curve models

In recent years,increasingly complex machine learning methods have become state-of-the-art in modelling wind turbine power curves based on operational data.While these methods often exhibit superior performance on test sets,they face criticism due to a perceived lack of transparency and concerns about their robustness in dynamic,non-stationary environments encountered by wind turbines.In this work,we address these issues and present a framework that leverages explainable artificial intelligence methods to gain systematic insights into data-driven power curve models.At its core,we propose a metric to quantify how well a learned model strategy aligns with the underlying physical principles of the problem.This novel tool enables model validation beyond the conventional error metrics in an automated manner.We demonstrate,for instance,its capacity as an indicator for model generalization even when limited data is available.Moreover,it facilitates understanding how decisions made during the machine learning development process,such as data selection,pre-processing,or training parameters,affect learned strategies.As a result,we obtain physically more reasonable models,a prerequisite not only for robustness but also for meaningful insights into turbine operation by domain experts.The latter,we illustrate in the context of wind turbine performance monitoring.In summary,the framework aims to guide researchers and practitioners alike toward a more informed selection and utilization of data-driven wind turbine power curve models.

基于微通道散热的板条激光放大器热仿真分析

众所周知,热效应是限制大功率高能量激光器发展的一大瓶颈,在高能激光产生的过程中伴随着大量的废热产生,影响高能量激光器的光束质量甚至会影响其正常工作。为了保证高能量激光器的稳定运作并研究其工作物质的散热过程中的热分布状态,本文建立了一种用于高能Zig Zag板条激光放大器的双端入水微通道散热模型,利用CFD模拟仿真软件在额定工况下对微通道与空腔热沉进行散热对比,还研究了模型的可变参量:通道高度、翅片厚度,以及水流量对于散热性能的影响。模拟研究发现本文提出的微通道热沉冷却效果优于全腔水冷效果,微通道热沉将晶体表面最高温差控制在4℃以内,表面温度也降低了32;同时在压降允许范围内优化通道参数能再将冷却效果提升10,实现增益介质分布式高效散热。

空调新风系统需求响应潜力评估及影响因素研究

需求响应是保障电力供需平衡的重要措施,空调是重要的需求响应资源。空调新风负荷能耗占比高,但是基于室内二氧化碳浓度的新风负荷参与电力系统需求响应的潜力尚不清晰。该文以办公建筑新风系统为例,分别以单位小时能耗最低和全天电费最低为目标,提出了新风系统短期响应和全天响应策略,并建立了相应的响应潜力评估方法。研究结果表明:室内二氧化碳浓度惯性小,新风系统调节速度快,是优良的短期响应资源,单位小时能耗可削减20%~100%,人员密度越低,响应潜力越大,夏季尖峰电价时段平均可削减34%的新风负荷。以峰谷分时电价为响应信号,全天总运行费用可节省14%。在此基础上,进一步探究了室内二氧化碳浓度上限、人员密度、换气次数和气候区对新风负荷响应潜力的影响规律。新风柔性为建筑参与电网响应提出了新的解决方案,对于改善电力供需矛盾有较高的应用价值。

面向无线无源印刷机状态监测的一种能量收集方法及装置设计

印刷机轮系是印刷机的重要组成部件,印刷机轮系的状态监测对于保障印刷品质量、设备安全具有重要意义。为解决印刷机内部无线状态监测系统的能源和续航问题,本研究提出了一种基于自供电技术的面向无线无源印刷机状态监测的能量收集方法,通过电磁式能量收集装置采集印刷机轮系的旋转机械能量,维持印刷机内部低功耗无线无源状态监测系统的数据获取。首先,调研了现代高速印刷机正常运转下轮系的转速特点;其次,设计了能量收集装置;之后,根据理论分析与有限元仿真结果,对装置结构进行了改进;最后,制作样机进行测试,并将仿真结果与实验结果相比较,验证了该能量收集方法的有效性。经实验验证,在1000r/m转速下,当外部负载电阻为50Ω时,该能量收集装置最大输出功率可达275.28mW。同时,该装置的电压与转速呈现良好的线性关系,证明其还具备作为转速监测传感器的潜力。

计及不确定风险和多主体协同的虚拟电厂参与主辅市场联合优化策略

虚拟电厂(virtual power plant,VPP)可聚合多利益主体的分布式资源(distributed energy resources,DER)参与电力市场,以深入挖掘分布式能源的调度潜力,如何考虑各运行主体的协同调度,提高整体收益成为当前亟需解决的重要问题。基于此,提出了计及风光及市场电价不确定风险和多主体协同的虚拟电厂参与主辅市场联合优化策略。首先,建立电动汽车群体(electric vehicle duster,EVC)的可调度域评估模型,在此基础上考虑VPP与EVC两主体的利益均衡,提出VPP与EVC主从博弈的主能量市场日前竞标模型;其次,考虑电池储能系统(battery energy storage system,BESS)快速充放电的特性,进一步提出VPP参与主能量市场和辅助调频市场的日前联合投标模型和VPP实时调整及调频响应模型;最后,在日前联合投标模型中引入条件风险价值(condition value at risk,CVaR),衡量日前投标收益与不确定风险的关系。基于某省电力市场规则进行算例仿真表明,所提VPP优化策略能通过提供调频服务和鼓励EV响应调度提高VPP的综合收益。