Advanced Materials Research Vols. 608-609

Abstract: The phase change thermal storage unit With Bushings Between Double Flow was proposed through adopting a kind of new phase change material (PCM), JDJN-60. In addition, the corresponding heating experimental device was built. The study with regard to the heat storage characteristic of JDJN-60 was performed. The results show that the thermal energy storage process has three stages and there is a certain undercooling of the PCM. The effects of natural convection on the heat storage and release process are different. The natural convection accelerates the liquefaction process and alleviates the solidification process.

Abstract: Paraffin/activated carbon composites as phase change energy storage materials were prepared by absorbing paraffin into activated carbon. In composite materials, paraffin was used as phase change material (PCM) for thermal energy storage, and activated carbon acted as supporting material, ethanol was the solvent. A series of characterization were conducted to analyse and test the performance of the composite materials, and differential scanning calorimeter (DSC) results showed that the PCM-2 composite has the melting latent heat of 51.7 kJ/kg with melting temperature of 60.4°C. Due to the capillary and surface tension forces between paraffin and activated carbon, the leakage of melted paraffin from the composites can be prevented. In a word, the paraffin/activated carbon composites have a good thermal stability and can be used repeatedly.

Abstract: This paper presents application of a CHB inverter based SESS. CHB inverter is characterized by cascade connection of multiple single-phase H-bridge (or full bridge) inverter cells. CHB inverter can make SESS flexible in circuit design, reduced voltage steps, and lower EMI. This paper presents circuit architecture design, modeling of CHB inverter based SESS, and control strategy focusing on power and energy balance control among Sub modules (SMs). The simulation results verify that the CHB inverter based SESS have a good performance in both fast power exchange and SM energy balance.

Abstract: The utilization of the solar cell effectively promotes the use of renewable energy. Since the light intensity changes with the time and the weather conditions, the output power of the photovoltaic (PV) cells is also unstable. It is a common way of using the storage device to stabilize the power fluctuation. Firstly, a control strategy of the hybrid energy storage consisting of battery and super capacitor is presented in the paper. Then the transient characteristics of photovoltaic systems with hybrid energy storage system (HESS) are investigated by simulation experiment, which include the transient behavior with a sharp change of light intensity and the transient characteristics in a three-phase short-circuit fault. The advantage of super-capacitor in the hybrid energy storage system is also analyzed in the transient process. Finally, some conclusions about the transient characteristics of the PV system with the HESS are summarized.

Abstract: Based on the comparison of battery energy storage system, super capacitor energy storage system, superconducting storage system, flywheel energy storage system, hybrid energy storage system composed by battery and super capacitor is proposed. By Analysis the performance of the system, it can be know that the system has characteristics of high specific power and high specific energy, and the battery and super capacitor device can be flexibly configured, which make energy storage system performance greatly improved. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Abstract: This paper describes the structure of energy storage system in smart grid, and analyzes the battery management system applied in the energy storage system. Battery temperature’s acquisition mode and the anti interference measures are studied. A battery state-of-charge (SOC) estimation method using the extreme accelerate correction method is proposed and the method is feasible to ensure the accuracy of SOC estimation. A battery voltage failure threshold table is constituted by extracting the important experimental data, and the safe using of the battery can be ensured by querying the threshold table. Now the battery management system could meet the needs of the actual operation of the battery energy storage system.

Abstract: Graphene-metal oxide composites as supercapacitor electrodes combine the large pseudocapacitance of metal oxides with the fascinating electrical and mechanical properties and large surface area of graphene. The synthetic methods for composites are reviewed, including in-siu synthesis, solution mixing, hydrothermal method, microware irradiation and electrochemical deposition. Among these techniques, the hydrothermal method offers an effective and simple way to anchor metal oxides on the 2D graphene sheet uniformly. Consequently, the composites exhibit high capacity, high rate capability and well reversibility, presenting promising prospects as supercapacitor electrode material.

Abstract: In order to improve the energy efficiency of electric vehicle (EV) power battery, and increase the start-up power of EV, a kind of maglev flywheel battery storage energy system is designed on EV, it is active suspension controlled at five degrees of freedom. The system suspension control principle is expounded, and the radial single freedom transfer function of the maglev flywheel is established combining with a digital PID control algorithm. The frequency spectrum characteristic of the transfer function and the flywheel rotor trajectory curve are simulated, and the 30000 r/min rotation experiment of the maglev flywheel battery prototype is realized. The experiment result shows that the maglev flywheel rotor may high speed and steadily spin, and has good energy storage ability. The maglev flywheel battery storage energy system can assist the EV power battery work, improves the battery charge and discharge properties and prolongs the service life of the motive power battery.

Abstract: In order to reduce the DVR manufacturing cost, we had better expand the range of the DVR compensation as far as possible in a certain energy storage capacity under the restricted condition of maximum output compensation voltage of the device. This paper adopted a fast- detection method in which the single-phase voltage is delayed 60ºso as to structure the virtual three-phase voltage, and ensured the minimum energy output of DVR based on the phasor diagram of the pre-sag load voltage. The characteristics of the fast response and the high conversion of the super conductor magnetic energy storage (SMES) are made full use of. Finally, through simulating MATLAB, this compensation method is proved to be capable of effectively reducing the active power output of DVR, fast compensating the voltage sag, as well as enlarging the compensation scope of DVR.

Abstract: Ni_0.76Co_0.24O_x xerogels were formed by the sol-gel method followed by heat-treatment in air. The structure and properties of these materials were characterized by using X-ray diffraction, TEM and N2 (77K) adsorption. Electrodes with the xerogels were activated by cyclic voltammetry (CV) and their capacitive performance was evaluated by galvanostatic technique in 7 mol/L KOH solutions. A maximum specific capacitance of 904 F/g was obtained by constant current discharge with a current density of 2.0 mA/cm² for the Ni_0.76Co_0.24O_x xerogels heat-treated at 250°C. High performance obtained indicates that these materials are promising electrode materials for supercapacitors.