Advanced Materials Research Vols. 512-515

Abstract: As part of micro grid, energy storage system provides an essential part in smart grid, it enables renewable, and is ready to be deployed today. This paper introduces the technology readiness levels (TRL), which can divide the investment process of energy storage into several phases, optimize the investment timing, and reduce the technology investment risk. This paper is aiming to give suggestion on the issues of energy storage system’s implementation process, and we analysis the feasibility of the standard in theory and verify it in a case study.

Abstract: Whatever types of batteries, when they work out of the normal temperature range, their performances greatly worsen. When the battery charges or discharges in a high rate, it would be quite possible to arouse thermal runaway had the heat generated not dissipated properly. This article commits itself to take the variation of the battery internal resistance into account to revise the overall temperature rising curve based on a simplified battery thermal model. By carrying out necessary experiments and using CFD simulation tool we get a better battery temperature rising curve and contour of internal temperature distribution under different operating conditions. It is applicable to provide reference for the thermal management of power batteries.

Abstract: Vanadium redox battery (VRB) system is a new type of energy storage system, which can be used to shave power grid peak, improve power quality, and smooth fluctuations of power and Voltage in photovoltaic and wind power systems. The state of charge (SOC) of VRB is an indication of how much energy is stored in the battery. Estimating the VRB SOC accurately in real time is very important when the battery is used to power system. In consideration of deficiencies of existing methods, a new approach is introduced to use Extended Kalman Filter (EKF) method. In this paper, state space model of VRB based on its equivalent circuit model is proposed, and SOC Estimation Using EKF Method for VRB is described in detail. By using Matlab software, it can be proved that the EKF method can estimate real-time SOC of VRB and is more accurate than existing methods.

Abstract: Recently, a lot of PV power systems ranging from 1MW to 10MW have been built in China. However, the power grid can’t accept so much PV power because of their oscillated output power. PV systems are affected by the weather condition a lot, such as the sunlight and the temperature. Embedding energy storage system into PV system could improve the grid-access performance of PV systems as well as expand the functions of original PV systems, including regulating power quality of grid. In this paper, PV-storage topology is presented and the flow direction control (FDC) method is described. Based on the operation data of a 100kW PV system in a certain place of China, simulation studies are performed. The result of simulation verifies the possibility and necessity of building the energy storage system in the PV system. With the decline of the cost of energy storage system and PV system, the development of renewable energy in China will be accelerated and supported by the combination of PV system and energy storage system.

Abstract: The ion-exchanger Mg_0.5Ti_0.5PO₄ of spinel type was prepared by means of the solid state reaction crystallization method, and was acid-modified. This inorganic ion-exchanger(Mg_0.5Ti_0.5PO₄) has the saturation capacity of exchange for Li⁺ higher than those for other alkali ions, the saturation capacity of exchange for Li⁺ reaches to 5.4mmol/g, MgTi-750(H) has a higher selectivity of ion exchange for Li⁺ than for other alkali ions.

Abstract: The manganese oxides (MnO₂) with nanostructures was fabricated with non-aqueous alcohol and aqueous solution of potassium permanganate (KMnO₄) at room temperature. The test results show that the nano-MnO₂ well coated on the surface of carbon nanotube (CNT), while the specific capacitance of the composites with MnO₂ deposited on singlewall carbon nanotube (SWNT) was better than coated on multiwalled carbon nanotube (MWNT). The specific capacitance of MnO₂ coated on SWNT film can reach 769F/g at scan rate of 5mv/s in the first cycle.

Abstract: Li_(1-2x)Co_xMnPO₄/C composite cathode materials for lithium ion battery are synthesized by sol-gel method with following heat-treatment in the air. Environment scanning electron microscopy measurements show that the particles are irregular and inhomogeneous, and that particle sizes slightly enlarge with the elevation of sintering temperatures. Powder X-ray diffraction analysis indicates that the samples are olivine-structured. Electrochemical tests indicate that the optimal sintering temperature registers 400 °C, and that the cyclic ability of LiMnPO₄ is greatly improved by doping Co²⁺. When tested at 0.02 C rate between 2.8 and 4.4 V, the initial discharge capacity of the sample with initial composition of x=0.07 sintered at 400 °C reaches 112.2 mAh/g , after 70 cycles, the capacities remain 58.8mAh/g.

Abstract: A inverse spinel-type metal compound [Mg₂Ti_0.5(PO₄)₂], was prepared by a solid state reaction crystallization method. The Li⁺ extraction/insertion with this material were investigated by X-ray, FT-IR spectroscopy, and Kd measurement, The acid treated samples had an ion exchange capacity of 8.7mmol/g for Li⁺. It had a memorial ion-sieve property for Li⁺.

Abstract: To overcome the risk of electrolyte leakage and the shortcoming of higher impedance at high frequencies for the conventional aluminum electrolytic capacitor impregnated with electrolyte solutions, solid aluminum electrolytic capacitor employing conducting polyaniline (PANI) as a counter electrode was developed. The as-fabricated solid capacitors have very low impedances at high frequencies and excellent thermal stability. The superior performances can be ascribed to high conductivity and good thermal stability of the camphorsulfonic acid (CSA)-dodecylbenzenesulfonic acid (DBSA) co-doped PANI.

Abstract: Battery capacity evaluation is a key work in wind\battery hybrid generation system optimization. Here a research about battery capacity evaluation of wind\battery hybrid generation system is made and a new way to evaluate the capacity is given. First, common evaluation methods such as integration peak value method are introduced. Then energy conversion constraints analysis in wind\battery hybrid generation process is given. Fake charge problem existed in integration peak value method is described comprehensively. At last, a new method to evaluate the battery capacity is put out.