Energy storage system is an effective means to overcome the fluctuation of wind power generation and improve electrical network stability. This paper briefly introduces the impact of wind power generation on the grid and different battery energy storage technologies first. Demonstration projects of combined wind power generation and energy storage systems is then discussed. This is followed by an outline of three main operating modes of the combined wind power generation and energy storage using batteries, including smoothing wind power fluctuation, tracking wind power schedule output and load shifting. Current status of control strategies and storage capacity for the combined wind power generation and energy storage systems are then presented. Finally, further research needed for the combined system is discussed and improvement on the economic aspects is concluded to be a key aspect for future research.

Traditional frequency regulation units rarely achieve real-time output equal to the theoretical values because of their inherent characteristics, leading to operation out of the economic zone. It is hard for these units to meet the demands of maintaining power system frequency stability with rapid development of grid involving renewable resources. Battery energy storage system (BESS) has advantages of fast response and precise tracking, providing a new frequency regulation method. On the basis of the use of energy storage for frequency regulation, the capacity configuration of BESS is made as an alternative to generator with the same capacity for the frequency regulation. A capacity control strategy for the energy storage has also been proposed. Exemplar calculations and comparative analysis are conducted to verify the feasibility of proposed capacity configuration methods and the reliability of the energy storage system for regulation.

Take the case of a self-designed radial magnetic bearing for magnetically suspended flywheels, the magnetic circuit on a radial magnetic bearing has been simulated in the ANSYS environment and theoretically analyzed. The simulation results agree with the theoretical analyses, indicating that the simulation results could be used for the designing within an allowable range of error.

Energy storage density is an important technical specification for the structure and materials design of flywheels. In this paper, theoretical analyses are carried out on the energy storage density of flywheels. Limiting factors on increasing energy storage density of flywheels are identified and analyzed. A simple correction method is put forward for the calculation of energy density of flywheels and data from the literature are used for the validation of the method. Currently, experimental flywheels in China have a linear velocity below abut 800 m/s with an energy density below 60 W·h/kg.

Energy saving is one of the important indicators to evaluate the performance of a combined cooling, heating and power (CCHP) system. In this paper, the principle of active energy storage regulation method for CCHP systems is introduced. A parameter termed relative energy saving ratio is used for the evaluation of energy consumption of the CCHP systems. Based on the analyses of load characteristics of users and performance of gas turbines under partial load conditions, energy saving and associated influence factors are investigated using cooling conditions and electrical demands of a typical restaurant in summer time. The results show that the active energy storage regulation method could improve all-operation performance of primer. The relative energy saving of a CCHP system without energy storage is 11.8%, whereas the relative energy saving of a CCHP with energy storage is 21.6%. The relative energy saving is affected by the coefficient of performance of electrical compression refrigeration system and the ratio of cold and electricity of users. The higher the coefficient of performance of the electrical compression refrigeration system, the lower the relative energy saving of CCHP. The relative energy saving increases with increasing ratio of cold and electricity of users.

Supercapacitor is a kind of energy storage devices which storage energy by the electrochemical double-layer or the redox reactions at or beyond the surface of the electrode. They have many advantages, such as high power density and long life cycles. It prospects broad applications. In this review, we give an introduction about the characteristics of electrode materials for the supercapacitors, focusing on therecent progress on carbon materials, transition metal oxide, conducting polymer and their composites.

After more than a decade LiFePO₄ has become a widely used cathode material for lithium ion batteries due to its intrinsic properties such as safety and stability. Its preparation method includes solid state reactions and liquid phase reactions, of which liquid phase route has advantages of unique morphology and sizes. This work summarizes our recent work on the conventional hydrothermal and anhydrous-solvothermal processes and sol-gel methods for preparing LiFePO₄ with special microstructures.

Because the complete reaction product of lithium and sulfur is Li₂S, the theoretic capacity of elemental sulfur cathode in a lithium sulfur battery is 1675mA·h/g, which is much higher than other cathode materials of LiFePO₄, LiCoO₂, et al. And sulfur has low price and non-toxic, which is an ideal cathode material. However, its electrical conductivity is very low, and the capacity declines rapidly with cycling. So it is necessary to improve the conductive performance of sulfur cathode and enhance its electrochemical properties. In this paper, the preparation method, structure and morphology, electrochemical properties of sulfur-based composite cathode materials are reviewed. The combination of sulfur with mesoporous carbon, CNTs graphene and polypyrrole respectively is discussed, and the future prospect of sulfur-based cathode material is also represented.

The gasification of coal can produce large amounts of fly ash, which still contains untapped charcoal. Fly ash was demineralized by flotation and activated carbons (ACs) were prepared by activation using KOH. The effect of preparation conditions on the performance of ACs was analyzed. The results show that: ① Total pore volume and micropore volume increased with the alkali-carbon ratio, while the content of mesopores decreased; ②The capacitance increased with the alkali-carbon ratio, but become stable after 2∶1; ③The electrochemical performance was improved by demineralizion; ④Activated carbon electrode shows a high capacitance at high current density and excellent cycling performance.

Mechanical properties of current collection foils, particularly the elastic moduli, and yield and fracture strengths, are critical for the design and fabrication of electrodes of Li-ion batteries. Characterization of these mechanical properties provides useful guidance for the design and subsequent manufacture of the current collectors. This paper reports our recent work on the mechanical properties of rolled copper foils and electrolytic copper foils for Li-ion batteries. Microtensile experiments were carried out and the mechanical properties are compared for two manufacturing processes and six different thicknesses. It was found that the elastic moduli were about 70 GPa and 50 GPa for electrolytic copper foils and rolled copper foils, respectively. The yield strength of the copper foils increased with decreasing thickness, showing a trend of smaller being stronger. To investigate fracture mechanisms of the copper foils, selected cross-sections of the copper foils were observed using a scanning electron microscope (SEM). The results suggested the electrolytic copper foils failed in the brittle fracture mode, whereas the failure of the rolled copper foils was through ductile fracture.

This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 1084 papers online from April 1,2014 to May 31,2014. 100 of them were selected to be highlighted. Layered oxide and high voltage spinel cathode materials are still under extensive investigations. Large efforts were devoted to Si based anode materials and electrolytes, composite carboneceous anode, solid state electrolytes. There are a few papers related to Li/S battery, Li-air battery and more papers related to cell analyses, theoretical simulations, and modeling.

Commercial lithium ion batteries using flammable nonaqueous electrolytes have that hidden safety problems. All-solid-state lithium ion batteries is one of the possible technologic approaches to address this problem. For practical applications, some scientific and technological barriers need to be overcome, including exploring solid electrolyte material with high conductivity and electrochemical stability; decreasing interface ionic transport resistance between solid electrolyte and electrode phase; suitable anode and cathode materials for all-solid batteries; production technologies for materials；design and manufacturing of batteries. This paper summarizes briefly the status of solid electrolyte materials, efforts of high-throughput calculation on solid electrolyte materials and the interface issues between electrode material and solid electrolyte.

In order to study the all-vanadium redox flow battery (VFB), a mechanistic model is developed based on the transport and reactions to simulate the effects of various electrode parameters on the battery's overall performance and internal polarizations for a VFB charged at isothermal and steady state. The parameters included the carbon felt's geometry structure parameters (thickness Lt, Compression ratio CR), electrical parameters (specific surface area a, electric conductivity) and operating parameter (charging current density i). Numerical simulations showed that when Lt increased from 1.5 mm to 3.5 mm, the terminal voltage drop is 3 mV only; when CR increased from 0.1 to 0.5, the terminal voltage drop is 16 mV; when a increased from 3.5×10⁴ m²·m^-3 to 3.5×10⁶ m²·m^-3, the terminal voltage drop is 30 mV; when increased from 18.9 S·m^-1 to 164.4 S·m^-1, the terminal voltage drop is 87 mV, and results also showed different two-dimensional over-potential distribution characteristics under different; when i increased from 100 mA·cm^-2 to 150 mA·cm^-2, the terminal voltage increase is 57 mV, if proportionally increased a, the terminal voltage increase is 46 mV only. Based on the terminal voltage and the over-potential distribution, the reasons for the effects of various parameters on the battery performance are discussed. The experimental validation showed similar results, which proved the reliability of the numerical simulation. Increasing CR, a and will significantly improve the battery performance. This should provide guidance to parameter design and to improve the performance of electrode material, and the improving of battery performances.

After an introduction of the traditional -fueled generator for emergency power suppply, this paper presents a new "mobile energy storage emergency power supply", in which a low noise and environment friendly ZnBr battery is applied, and detail explain some issue, such as shockproof, assembling method etc.. We solved sevral key problems for installing the ZnBr battery combine in a vehicle and complete the first vehicular flow battery emergency power supply. Its future prospect is also discussed based on our practice.

Large-scale introduction of electric vehicles will have a significant impact on the present energy storage mode. Based on the analysis of EV batteries and large-scale energy storage mode both at home and abroad, we proposed a family base distributed storage concept. This paper presents its technical solutions and scope of application. Its application status abroad and government policy support. In addition, we analyze its relationship with electric vehicle's energy storage and make a proposal of utilizing the valley electricity. The application prospects of this new mode are also discussed.

The present battery management system for energy storage is similar to that for electric vehicle batteries. It can be applied to small capacity battery systems and has relative simple function and low timeliness. Large capacity cells in series for energy storage needs advanced battery management system with higher efficiency. A three layer management system is presented to attack the problems raised for large energy storage batteries. Hardware and software of bottom layer BMU, middle layer BCMS and top layer BAMS are introduced in detail. The hierarchical system of energy storage battery management has following functions: measurement and calculation, cell balance, high voltage safety management, data statistic and storage, charging and discharging managements, warning and communication.