Electric double-layer capacitor using organic electrolyte

Electric double-layer capacitors (EDLCs) based on charge storage at the interface between a high surface area carbon electrode and a propylene carbonate solution are widely used as maintenance-free power sources for 1C memories and microcomputers. New applications for electric double-layer capacitors have been recently proposed. The popularity of these devices is derived from their high energy density relative to conventional capacitors and their long cycle life and high power density relative to batteries. The performance of the capacitor depends not only on the material used but also on the construction of the cells. The material, construction and performance of coin-type capacitors for memory protection and power capacitors for large power sources are described.     

Research progress of carbon-based lithium ion capacitor

新能源体系的建设和电子设备的飞速发展对储能器件提出了更高的要求,即要求其同时兼具较高的能量密度和功率密度。锂离子电容器（LIC）是一种基于锂离子电池（LIB）和超级电容器（EDLC）双重储能机制的储能器件,兼具超级电容器良好的功率特性和锂离子电池较高的能量密度,有望应用于混合动力汽车、轨道交通、智能电网、能源工程等领域。从锂离子电容器未来的产业化角度出发,炭材料因为资源丰富、制备简单和廉价易得是锂离子电容器的首选材料。本文综述了活性炭等正极炭材料、石墨等负极炭材料、电解液以及锂离子电容器工艺方面的研究进展,并对锂离子电容器未来的发展方向和发展前景作出了展望。     

Electrochemical performance of lithium ion capacitors using high-capacitance Li2NiO2/AC as the negative electrode

兼具锂离子电池高能量密度和双电层电容器高功率特性的锂离子电容器成为了现今超级电容器性能提升的重点发展方向。本工作以高富锂金属氧化物Li2NiO2为锂离子电容器用负极锂源,将其与活性物复合组成正极电极,并制备出“无金属锂片”预嵌锂过程的300 F锂离子电容器,考察了金属氧化物Li2NiO2的理化性能与电化学特性、不同Li2NiO2添加量对锂离子电容器样品的电化学性能影响。结果表明,Li2NiO2材料具有398 mA·h/g的首次不可逆容量,首次放电不可逆率为94.8%。添加15%～20% Li2NiO2的样品在10 A电流下具有大于75%倍率特性以及91%的容量保持率。当Li2NiO2添加量为20%时,样品在1 A条件下具有400 F的容量,15.5 W·h/kg的能量密度以及11.3 kW/kg的功率密度,是一种制备工艺简单、性能优异的新型锂离子电容器。     

Development of coin-type lithium-ion rechargeable batteries

We developed coin-type lithium-ion rechargeable batteries made of crystalline V₂O₅ for the cathode and pitch-based carbon for the anode. We optimized the capacity balance of cathode and anode materials. The batteries have a high operating voltage of about 2.7 V and excellent charge/discharge cycle characteristics. We also designed the batteries whose cathode potential is over 3 V versus lithium when the batteries are overdischarged to 0 V. Therefore, the batteries have excellent recovery characteristics even after overdischarge. The batteries have high energy density (about 100 Wh/l) which is about two times that of the coin-type NiCd batteries. It can serve as a memory backup power source with a single battery.     

无功功率补偿装置的改进

本文介绍一种计算机控制的工厂供电系统的无功功率补偿装置,它包括一种大功率的无冲击电流的硅可控开关,用以通、断电容器电路,这种设备具有高可靠性、长寿命的特点,达到节电的目的.     

Production of hydrogen via methane reforming using atmospheric pressure microwave plasma

In this paper, results of hydrogen production via methane reforming in the atmospheric pressure microwave plasma are presented. A waveguide-based nozzleless cylinder-type microwave plasma source (MPS) was used to convert methane into hydrogen. Important advantages of the presented waveguide-based nozzleless cylinder-type MPS are: stable operation in various gases (including air) at high flow rates, no need for a cooling system, and impedance matching. The plasma generation was stabilized by an additional swirled nitrogen flow (50 or 100 l min⁻¹). The methane flow rate was up to 175 l min⁻¹. The absorbed microwave power could be changed from 3000 to 5000 W. The hydrogen production rate and the corresponding energy efficiency in the presented methane reforming by the waveguide-based nozzleless cylinder-type MPS were up to 255 g[H₂] h⁻¹ and 85 g[H₂] kWh⁻¹, respectively. These parameters are better than those typical of the conventional methods of hydrogen production (steam reforming of methane and water electrolysis).     

抽凝机组耦合热电转换辅助调峰系统参数设计

  目的  为适应新能源电力并网需求,原有抽凝热电联产机组深度调峰供热改造已为重要途径之一。现有包括电热泵和电锅炉在内的热电转换装置为辅助火电机组调峰提供了潜在途径。  方法  以350 MW抽凝机组为例,建立了以热电转换装置辅助调峰参数优化模型,重点分析了热电转换设备参数对深度调峰性能的影响;其次,分别对比了电热泵和蓄热电锅炉两种典型热电转换系统在不同装置容量、不同放热速率下的调峰深度;最后,介绍了300 MW燃煤机组的煤耗率与污染物排放水平,指出本系统的节能效益,并给出热电转换装置的最优参数。  结果  结果显示:当电热泵的热功率为100 MW、放热速率与热功率相匹配也为100 MW时,机组的调峰深度达到最大值,为73 MW左右;当蓄热式电锅炉的电功率为45 MW、放热速率为100 MW时,机组的调峰深度达到最大值,为70.05 MW。蓄热式电锅炉的储热量在24 h中内略有增加,净储热量的数值为967.5 kWh。  结论  功率和放热速率是衡量热电转换装置辅助机组调峰能力的重要参数,且二者之间要有一定程度上的匹配性,针对不同情景灵活匹配热电转换装置的类型与参数可大幅提升机组的调峰深度。     

High-speed, high-horsepower electric motors for pipelinecompressors: available ASD technology, reliability, harmoniccontrol

At a time when the US natural gas pipeline infrastructure needs to be upgraded with new high-horsepower compressors to meet additional capacity demands, there exists an electric motor technology suitable for the task. The power electronic adjustable speed drive (ASD) controlled electric motor offers superior economics of initial, operating and maintenance costs compared to natural gas powered equipment. Natural gas pipeline deregulation is causing pipeline operators to evaluate electric drives as an alternative to gas driven equipment. This paper provides a needed summary of the potential for load building that is being offered to the electric power industry by the economics of the deregulated natural gas transmission industry. The gas transmission industry needs to upgrade equipment for more capacity. The new high speed electric motor technology discussed in this paper provides means for upgrading, at a fraction of the life cycle costs of conventional gas powered equipment     

LiFePO4 as an optimum power cell material

Nano-crystallized LiFePO₄ has been synthesized with a simple three-step-synthesis technology in the presence of nano-ferric oxide as iron source and polyacence (PAS) as a reductive agent and high conductive carbon source. The use of PAS increases the conductivity and prevents the particles growth. The most feasible calcined temperature and time was investigated and the best cell performance was delivered by the sample calcined at 700 °C for 4 h. This material shows excellent specific capacity and cycle efficiency at high current rates, almost no capacity loss can be observed up to 100 cycles which make it more superior as an optimum power cell cathode material.     

Lithium-ion rechargeable cells with polyacenic semiconductor (PAS) and LiCoO2 electrodes

Polyacenic semiconductor (PAS), heat-treated at 700°C, has a lithium intercalation capacity as high as 438 mAh g⁻¹ which is higher than the theoretical capacity of 372 mAh g⁻¹ for graphite. The electrochemical behaviour of PAS is examined by studying Li/PAS and Li/graphite cells. In a PAS or graphite anode, three reactions are distinguished: (i) reaction of lithium with the Teflon binder; (ii) decomposition of electrolyte, and (iii) intercalation of Li⁺ ions. Two laboratory cells with liquid organic electrolyte or polymer electrolyte and PAS as the anode demonstrate that PAS is a promising anode material for lithium-ion batteries.     

Design consideration of sustainable self‐sufficient energy system using ferroelectric material for wearable healthcare

Design of the sustainable self‐sufficient energy generator and storage devices using ferroelectric material were considered for wearable healthcare device. Recently, personal health‐monitoring system is expected to be one of the most important and attractive applications of wearable electronics. It becomes more important for us to develop power generator and storage devices used in monitoring our health condition status on an aging society. The power generator and storage devices are desirable to be embedded into clothes or textile intangibly. In this paper, button type solar cell for power generator and film capacitor on fiber for power storage were considered by using ferroelectric material. The target power consumption for wearable healthcare device is more than 3.6 mW for communication means and sensing ECG, SpO₂, temperature, heart rate, and blood pressure that were essential for our health condition monitoring. The target capacity of power storage is more than 150 mAh for 5 days' operation. Clothes are thought to be suitable for embedding sufficient energy system. One proposed circuit that consists of solar cell and film capacitor is considered. The button type solar cell of the four pieces of 20 mm diameter and the film capacitor on fiber are proposed as power generator and storage. The proposed circuit will make it possible to use the healthcare devices more than 5 days without sunshine when we put on clothes of more than 160 g such as thin coat or outerwear. Moreover, the proposed circuit will make it possible to use the devices more than 30 days without sunshine when we put on clothes of more than 960 g such as thick coat or outerwear. As we don't forget to put on clothes that embedded the self‐sufficient energy system, the self‐sufficient system will become useful for sustainable society in the future. Copyright © 2016 John Wiley & Sons, Ltd.     

智能电网地县调控一体化技术的模式和应用

阐述了为满足调度业务和监控业务而提出的地县调控一体化关键技术,此模式建设在调度监控功能、系统互备、前置级互备、系统维护的综合优势。并实现了在二次设备模型、智能告警信息分流、设备运行状态监视和高级应用技术、AVC无功优化等技术上的融合。经实践证明,此架构模式符合电力调度生产的需求。     

Balancing control method by dispersed generators based on H∞ control theory in DC power feeding system

Recently, dispersed generators have been installed in distribution network to supply power to commercial facilities. Renewable energy generation contains output power fluctuations and distributed generator produces sluggish response for power demand. In order to overcome these problems, an ultra capacitor energy storage system is used for compensating the instantaneous power imbalance. However, use of a large capacity ultra capacitor energy system increases system cost. In addition, PPSs (Power Producer and Supplier) that own these generators are supposed to achieve 30-min balancing control for stable supply of electric power. This paper proposes a control system to achieve both 30-min balancing control and interconnection point power flow control by using a fuel cell and an ultra capacitor based on the H_∞ control theory. Besides, remaining storage energy of the ultra capacitor is controlled to be constant to maintain compensation capability. Effectiveness of the proposed control system is verified by using simulation results.     

High-rate capable organic radical cathodes for lithium rechargeable batteries

Poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) is the most common active material with a stable radical molecular structure used for lithium rechargeable cells. Because it is an organic active material, PTMA can be dissolved easily in various solvents. Using a solution of active material in the electrode making process, we formed an extremely large surface area between the active material and the conducting additive. The electrode has excellent power capability and can be charged and discharged in 1 min. We believe that this cell can be used like an electric double layer capacitor. We also believe that the cell, whose cycle life is good, retaining 89% of original capacity after 1000 cycles, can be put into practical use.     

Efficiency of wind energy utilization for electricity and heat supply in northern regions of Russia

The paper describes a method for assessing the economic efficiency of wind energy utilization within small autonomous systems for both electricity and heat supply. The obtained analytical solution allows the simplification of calculations in comparison to the methods of chronological modeling and numerical algorithms for application of the convolution method.The economic effect of using wind turbines is assessed for remote communities of the extreme north of Russia with a maximum electric load of 200 kW for the turbines with a capacity from 30 to 800 kW, taking into account variation of possible growth rates of fossil fuel price for back-up sources of electric and heat energy.The calculations performed have shown that at the existing and forecasted rates of fuel price escalation, the economic effect of using surplus (as a result of mismatch in production and consumption) electric energy for heat supply will be 1.5–2.0 times higher. In this case, the optimal capacity of wind turbines can substantially exceed electric load power (two to four times).     

A direct methanol fuel cell system to power a humanoid robot

In this study, a direct methanol fuel cell (DMFC) system, which is the first of its kind, has been developed to power a humanoid robot. The DMFC system consists of a stack, a balance of plant (BOP), a power management unit (PMU), and a back-up battery. The stack has 42 unit cells and is able to produce about 400 W at 19.3 V. The robot is 125 cm tall, weighs 56 kg, and consumes 210 W during normal operation. The robot is integrated with the DMFC system that powers the robot in a stable manner for more than 2 h. The power consumption by the robot during various motions is studied, and load sharing between the fuel cell and the back-up battery is also observed. The loss of methanol feed due to crossover and evaporation amounts to 32.0% and the efficiency of the DMFC system in terms of net electric power is 22.0%.     

A collaborative operation method between new energy-type dispersed power supply and EDLC

In this paper, the modified Euler-type moving average prediction (EMAP) model is proposed to operate a new energy type dispersed power supply system in autonomous mode. This dispersed power supply system consists of a large-scale photovoltaic system (PV) and a fuel cell, as well as an electric double-layer capacitor (EDLC). This system can meet the multi-quality electric power requirements of customers, and ensures voltage stability and uninterruptible power supply function as well. Each subsystem of this distributed power supply contributes to the above-mentioned system performance with its own excellent characteristics. Based on the collaborative operation methods by EMAP model, the required capacity of EDLC to compensate the fluctuation of both PV output and load demand is examined by the simulation using software MATLAB/Simulink, and, response characteristics of this system is confirmed with simulation by software PSIM.     

10 kV集合式并联电容器的选择与应用

介绍了新疆哈密地区巴里坤县110kV变电所安装的集合式并联电容器成套装置,对无功补偿容量的确定、集合式并联电容器及其配套设备型式的选择作了说明,以及运行过程中可能出现的涌流、过电压、电网谐波放大问题进行了分析,对变电站的无功补偿装置提出建议：按照变电站的无功补偿装置,仅补偿站内无功损耗的原则来确定变电站无功补偿容量;采用可调容集合式并联电容器配套的高压可调容智能综合控制器,该装置可根据变电站的功率因数和电压水平来调节有载调压变压器分接头和自动投切集合式并联电容器。     

Integration of an Energy Capacitor System With a Variable-Speed Wind Generator

This paper presents a system using an energy capacitor system (ECS) to smoothen the output power fluctuation of a variable-speed wind farm. The variable-speed wind turbine driving a permanent-magnet synchronous generator is considered to be connected to the ac network through a fully controlled frequency converter. The detailed modeling and control strategy of the frequency converter as well as variable-speed operation of a wind turbine generator system are demonstrated. Afterward, a suitable and economical topology of ECS composed of a current-controlled voltage-source inverter, dc–dc buck/boost converter, and an electric double layer capacitor (EDLC) bank is presented, including their control strategies. Exponential moving average is used to generate the real input power reference of ECS. Another novel feature of this paper is the incorporation of a fuzzy-logic-controlled reference signal adjuster in the control of the dc–dc buck/boost converter, in which the stored energy of the EDLC bank is utilized in an efficient way. Due to this controller, the energy storage capacity of the EDLC bank can be reduced in size, thus resulting in reduction of the overall cost of the ECS unit as well as decrease in irrepressible operations during high and low energy levels of the EDLC bank. Finally, extensive simulation results are presented that validate the effectiveness of the proposed system to smoothen the output power fluctuation of the variable-speed wind farm.