HEV用MH/Ni电池系统的研发现状

综述了混合动力电动车(HEV)用氢镍(MH/Ni)电池系统的国内外发展状况.对现阶段国内相关系统有待进一步改善的电池一致性、超高功率充电接受、荷电态(SOC)精确估算和价格等进行了分析.     

Effect of CuO addition on electrochemical properties of AB3-type alloy electrodes for nickel/metal hydride batteries

In order to improve overall electrochemical properties of AB₃-type hydrogen storage alloy electrodes, especially the cycling stability, CuO was added to the electrode. Electrochemical properties of the electrodes with and without additives were studied. Cyclic voltammetry and SEM results show that CuO is reduced to Cu during the charging process and the fine Cu particles deposit at surface of the alloy particles. The as-deposited Cu particles form a protective layer to increase electronic and heat conductivity of the electrodes and thus improve maximum discharge capacity, high rate dischargeability, cycling stability and dischargeability at high temperature of the electrodes. The maximum discharge capacity increases from 314 mAh g⁻¹ (blank electrode) to 341 mAh g⁻¹ (3.0 wt.% CuO) and the capacity retention rate at the 200th cycle increases from 71.6% to 77.2% (2.5 wt.% CuO).     

联合时空特征的视频分块压缩感知重构

为了提高视频压缩感知(CS)重构算法的率失真性能,该文提出利用视频的时空特征进行联合重构。为了不引入过多的复杂度,采集端以固定采样率对帧内各块进行测量;重构端则在最小全变差(TV)重构模型的基础上,分别加入利用时空自回归(AR)模型和多假设(MH)模型所形成的正则化项,以提高预测-残差重构的性能。另外,考虑到视频源的统计特性在时空域中是动态变化的,讨论了5种不同的帧间预测模式对重构精度和重构计算复杂度的影响。仿真实验表明,所提出的重构算法能够以一定的计算复杂度为代价有效地改善视频重构质量,且在关键帧采样率高于非关键帧的情形下,帧间预测模式的改善也可一定程度上提高视频重构质量。     

Hydrogen storage behavior of nanocrystalline and amorphous La–Mg–Ni-based LaMg12-type alloys synthesized by mechanical milling

Nanocrystalline and amorphous LaMg₁₁Ni+x% Ni (x=100, 200, mass fraction) alloys were synthesized by mechanical milling. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. The gaseous hydrogen absorption and desorption properties were investigated by Sievert's apparatus and differential scanning calorimeter (DSC) connected with a H₂ detector. The results indicated that increasing Ni content significantly improves the gaseous and electrochemical hydrogen storage performances of the as-milled alloys. The gaseous hydrogen absorption capacities and absorption rates of the as-milled alloys have the maximum values with the variation of the milling time. But the hydrogen desorption kinetics of the alloys always increases with the extending of milling time. In addition, the electrochemical discharge capacity and high rate discharge (HRD) ability of the as-milled alloys both increase first and then decrease with milling time prolonging.     

MH/ATH/纳米硅树脂阻燃电缆料的制备与研究

以LDPE、EVA为基体,MH、ATH、纳米硅树脂粉为阻燃剂,通过挤出造粒、注塑成型制得高性能无卤少烟阻燃电缆料。通过极限氧指数、万能电子拉力机、热重分析、傅里叶红外等研究手段研究电缆料的阻燃性能、耐热性能及其力学耐油耐老化性能。结果表明:P2体系有较好的阻燃性、耐热性、耐油、耐老化以及良好的力学性能,适合用作对阻燃要求较高的阻燃电缆料。     

Effects of compaction pressure on the electrochemical properties of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 metal hydride electrodes

In this work, the negative electrodes of the nickel-metal hydride rechargeable batteries were prepared at different compaction pressures. The maximum discharge capacities and cycle stabilities of the electrodes were measured by means of electrochemical method. The crystal structures and surface morphologies of the alloys were intensively studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS), respectively. Based on these observations, the effects of compaction pressure on the electrochemical properties of the electrodes were systematically investigated. The results showed that the electrode prepared at a compaction pressure of 25 MPa exhibited the best discharge capacity and better cycle stability.     

Rare earth-Mg-Ni-based hydrogen storage alloys as negative electrode materials for Ni/MH batteries

This review is devoted to new rare earth-Mg-Ni-based (R-Mg-Ni-based) hydrogen storage alloys that have been developed over the last decade as the most promising next generation negative electrode materials for high energy and high power Ni/MH batteries. Preparation techniques, structural characteristics, gas-solid reactions and electrochemical performances of this system alloy are systematically summarized and discussed. The improvement in electrochemical properties and their degradation mechanisms are covered in detail. Optimized alloy compositions with high discharge capacities, good electrochemical kinetics and reasonable cycle lives are described as well. For their practical applications in Ni/MH batteries, however, it is essential to develop an industrial-scale homogeneous preparation technique, and a low-cost R-Mg-Ni-based electrode alloy (low-Co or Co-free) with high discharge capacity, long cycle life and good kinetics.     

Thermal behavior of overcharged nickel/metal hydride batteries

This work provides a two-dimensional thermal model for cylinder Ni/MH battery. Thermal model is developed to analyze the thermal behavior of the battery when charged and overcharged. Quantity of heat and heat generation rate of the battery during charge and overcharge period are studied by quartz frequency microcalorimeter. Heat generation curve is fitted into a function, and heat transport equation is solved. Analysis with the model and experiment show that temperature rise is about 3 °C and difference between the model and the experiment is no more than 0.1 °C.     

贮氢合金V3TiNi0.56Mx耐腐蚀性能研究

钒基固溶体贮氢合金在KOH电解质溶液中容易腐蚀,导致合金的电化学循环稳定性差,限制了钒基固溶体贮氢合金在Ni/MH电池中的应用.通过测试贮氢合金V3TiNi0.56Mx(M=Al、Cr,x=0.1、0.3)在KOH溶液浸泡过程中组织结构变化和腐蚀电位、交流阻抗谱等,研究了钒基固溶体贮氢合金V3TiNi0.56Mx的耐碱液腐蚀性能.结果表明:钒基固溶体贮氢合金在碱液中的腐蚀原因是作为导电集流体的TiNi第二相在KOH溶液中的不断溶解;在合金V3TiNi0.56中添加Al和Cr元素,可阻止合金中分布于晶界的TiNi第二相的溶解,使合金的腐蚀电位提高,从而提高钒基固溶体贮氢合金的酎碱液腐蚀能力.     

Magnetic and optical properties of amorphous NdFeCo thin films by pulsed laser deposition technique

Rare earth and transition metal doped (NdFeCo) thin films were fabricated on Si (100) substrate by pulsed laser deposition technique keeping the substrate at constant temperature of 300 °C. A KrF Excimer laser (248 nm, 20 ns) was used as an energy source for the deposition. Thin films were deposited without and under the influence of transverse magnetic field applied across the plume. The applied magnetic field was varied from 3 to 6 kOe. The deposited films were characterized by XRD, FESEM, VSM and SE (Spectroscopic Ellipsometry). The deposited films were amorphous in nature. All the films regardless of the applied magnetic field exhibit perpendicular magnetic anisotropy. The thickness of the thin films was found to increase monotonically from 166 to 266 nm with the increase in the applied external magnetic field. The saturation magnetization has a maximum value of 1682 emu/cc for the film deposited under 4.5 kOe magnetic field. The value of optical band gap energy for the same film is found to have a maximum value of 3.1 eV. The values of both the saturation magnetization and the band gap energy were decreased with the increase in the applied magnetic field.