Advanced Materials Research Vols. 512-515

Abstract: Wind farms with vanadium battery energy storage system are recognized and welcomed. Against the phenomenon of current distribution unreasonable while vanadium batteries are directly paralleled, a control strategy of vanadium battery parallel based on the state of charge (SOC) is proposed. The current control formula is given in this paper. Vanadium batteries are paralleled to adjust the power grid at the exit of wind farms by the bidirectional DC/DC converter. A wind farm model with vanadium battery energy system is simulated on MATLAB/Simulink. The simulation results show that this system can adjust the power grid of wind farms and achieve the goal that the charging and discharging of vanadium batteries are determined by their SOC, avoiding the overcharge or over-discharge.

Abstract: Take the 60Ah lithium iron phosphate battery equipped for an electronic vehicle as research object, develop the Battery Management System (BMS) and process the bench test. The system uses LTC6802 chip to implement local electronic information collection unit, uses the resistance-voltage distributing principle to implement the high-voltage collecting and insulation resistance detecting, uses MC9S12XDP512 chip to implement the top-level data processing and vehicle information interaction. Bench test shows the designed BMS can monitor all states of the battery pack and compute in real time. At the same time BMS can communicate with the Vehicle Control Unit (VCU) reliably.

Abstract: Integrated prediction models on injection-production operation of Salt cavern underground gas storage are built. Simulation prediction research on performance of cavern and wellbore is presented in emergency operation, normal peak load operation, stable operation and intermittent operation modes. The results show that cumulative production gas volume is most in normal peak load operation mode, but cumulative production gas volume is least in stable operation mode. Cumulative injection gas volume is most in emergency operation and normal peak load operation mode, but cumulative injection gas volume is least in intermittent operation mode. At the same time, long-term emergency operation and intermittent operation will be avoided for guaranteeing good operation characteristic of salt cavern gas storage.

Abstract: A prototype of flywheel energy storage system is developed for light rail-trains in cities to store the braking energy. The prototype is designed to have a rotor of 100kg rotating at up to 27000rpm, which can store 1kWh energy and supply 10kW maximum power. Main works and results are described. Difficulties and some key techniques are presented. Test of the system operation is still not finished. Now the system is able to run at 16800rmp. Maximum power output is 3kWh.

Abstract: Current source converter (CSC) can control power transfer between superconducting coil and the AC power system, which is the key component of superconducting magnetic energy storage (SMES). This paper presents an improved state-feedback control for CSC of SMES. Adopting the discretization method, the design of decoupled state-feedback control system is simple and straight. To overcome the drawbacks of the discretization method and improve the control system dynamics, the effect of the control time delay is considered. Furthermore, by selecting the current error vector and the output voltage error vector as the additional state variables, a linear state feedback loop is added to the control system to achieve the feature of deadbeat. The steady state performance and dynamic response are investigated. MATLAB simulation is performed to evaluate the performance of the proposed control method.

Abstract: We investigate Zn/MnO₂ Leclanché cell employing inorganic MCM-41 membrane separator. MCM-41 membrane is developed onto zinc anode substrate from dip coating procedure, performed at room temperature. The parent solution for synthesis consisted of quarternary ammonium surfactant, cethyltrimethylammonium bromide C₁₆H₃₃(CH₃)₃NBr (CTAB) as the organic template, sodium hydroxide, deionized wate_{Subscript text}r, ethanol and tetraethylorthosilicate (TEOS). Zn/MCM-₄₁/MnO₂ cell, about the size of R2025 coin cell, is fabricated both in monopolar and bipolar designs. Bipolar cell configuration enhances the cell performance markedly. The cell demonstrates volumetric energy density - 42 Wh/l for bipolar design and 12 Wh/l for monopolar design, rated at continuous current drain of 1 mA.

Abstract: Ag/graphene nanocomposites were prepared by the reduction of silver acetate (CH3COOAg)/graphene oxide with hydrazine gas. The samples were characterized by X-ray diffraction and scanning electron microscopy. The electrocatalytic activities of the synthesized samples for hydrazine and formaldehyde oxidation were also investigated by cyclic voltammetry. The results show that Ag/graphene nanocomposites can be prepared by this novel and simple process. The samples present high electrocatalytic activity for hydrazine and formaldehyde oxidation.

Abstract: Based on power system static voltage stability constraints, by theoretical analysis, calculation method of injection power for each node in power system is given. Compared with power flow simulation, results show that this method can be used to obtain nodes with relative large injection power, and calculation accuracy in a certain extent depends on the accuracy of power system Thevenin equivalent impedance. In addition, the application of energy storage systems to improve wind farm power injection is analyzed preliminarily. Simulation results show that locations of energy storage system in power system have impacts on the improvement of wind farm power injection.

Abstract: This paper described the liquid flow battery system with graphite felt electrode and a single electrolyte, lead(II)in methanesulfonic acid. The kinetics behavior, cyclic voltammetry behavior and effects of treatment methods on kinetics behavior of Pb(II)/Pb couple were studied. The results show that the equilibrium electrode potential Pb(II)/Pb couple was -0.228V and the Pb(II)/Pb couple on graphite felt electrode had a good kinetics behavior. The cyclic voltammetry behavior of Pb(II)/Pb couple on graphite felt electrode was studied, and the oxidization and reduction peak potentials were -0.055V and -0.44V, respectively. The graphite felt treated with sulfuric acid had little oxidization and reduction peak potentials difference, and showed good electro-catalytic activity for Pb(II)/Pb couple.

Abstract: Vanadium Redox Flow Battery (VRB) holds unique characteristic as the power and capacity of the physical structure of independent design, which determines VRB different from other battery types in operating characteristics by taking unique operation modes under the circumstance of module degradation or failure in some cases. Paper focuses on how to ride through the case of VRB system with partial degradation or failure during the normal operational conditions, launched a comprehensive experimental study and theoretical analysis. The paper analyzes several situations from the point of view of the battery physical components which should lead VRB system partial failed, and simulated the battery partial degradation or failure by experimental means, and carried out two operation modes to respond to different partial failure situations, which including the use of lower rated power and the use of times rated power. Study proved that those two modes operated in the case of VRB partial failure conditions, has no significant effect to VRB Energy Storage System (ESS) efficiency, as well as be helpful to improve a higher reliability of VRB energy storage system. This paper takes the lead in studying the operational characteristics of VRB- ESS from the angle of partial degradation or failure conditions, which has practical engineering significance for developing VRB -ESS demonstration.