A robust cell voltage monitoring system for analysis and diagnosis of fuel cell or battery systems

Cell voltage monitoring (CVM) systems are essential for the operation of fuel cell stacks and some battery systems, in the field as well as in the laboratory, because they allow the diagnosis and correction of problems that would otherwise go unnoticed and cause impaired performance or even permanent damage. A robust, safe, and low-cost design for a CVM unit is presented, using electromechanical relays as multiplexing switches. Some examples from the application of the unit on the University of Delaware's fuel cell battery hybrid buses are presented, including its use in automatically correcting anode flooding and diagnosing air channel blockage.     

Lithium insertion/extraction mechanism in alloy anodes for lithium-ion batteries

The electrochemical performance of alloy anodes has been reviewed in a previous paper [1]. In this work, the fundamental understanding of lithium-insertion/extraction mechanism in alloy anodes is discussed. The article summarizes the different types of lithium-reaction processes observed in Si, Sn, Sb, Al, Mg and their alloys, with particular emphasis on the characteristics unique to alloy anodes, including the sloping voltage profiles, lithiation amorphization, cycling hysteresis and reaction-potential depression. These unique characteristics are discussed with respect to the effect of interface and surface energies on the phase transformation and thermodynamic stability of fine alloy particles.     

Facile synthesis of MTaO4 (M = Al,Cr and Fe) metal oxides and their application as anodes for lithium-ion batteries

Ternary metal oxides have attracted much attention in energy storage fields. Herein, tantalum-based oxides MTaO₄ (M = Al, Cr and Fe) are synthesized by a facile co-precipitation method, and their performance as lithium-ion battery anodes are evaluated. Among them, the FeTaO₄ electrode presents superior electrochemical performance compared to the MTaO₄ (M = Al and Cr) and a reversible capacity of more than 200?mAh?g^?1 can be maintained after 100 cycles, while a capacity of 53.6 and 128.9?mAh?g^?1 can be obtained at the same condition for AlTaO₄ and CrTaO₄, respectively. The explanation that FeTaO₄ exhibits the excellent electrochemical performance in MTaO₄ (M = Al, Cr and Fe) are further discussed.     

基于单片机的善电池组在线监测维护系统

本文设计实现了一种具有蓄电池组在线监测功能和大功率恒流放电智能负载功能的系统。该系统以单片机为核心控制恒流放电,在放电过程中测量电池电压、放电电流、系统温度并记录数据。系统采用了PWM控制技术,电流控制精度高,放电电流稳定,避免了用正温度系数负载稳定性和可控性差的缺点。     

电动自行车20GNY5.0蓄电池组的研制

本文采用由新型泡沫式镍正极和拉浆式镐负极制成标称容量为5Ah的D型镐镍电池,并按特定的分选原则和组合方式,制备了性能优良的电动自行车用24V,5Ah镉镍电池组。     

锂离子电池发展的前瞻——第14届国际锂电池会议评述

介绍了2008年6月22-28日在中国天津召开的第14届国际锂电池会议的学术发展情况.具有较好安全性能的磷酸铁锂正极材料和具有较高倍率特性和较好循环性能的纳米电极材料是最近的研究热点;改进负极材料和电解质,是进一步改善锂离子电池安全性能的关键;优化制备和平衡电池组技术,是亟待解决的动力电池的关键技术.     

Effects of the starting materials and mechanochemical activation on the properties of solid-state reacted Li4Ti5O12 for lithium ion batteries

Li₄Ti₅O₁₂ was synthesized by a solid-state reaction between Li₂CO₃ and TiO₂ for applications in lithium ion batteries. The effects of the TiO₂ phase and mechanochemical activation on the Li₄Ti₅O₁₂ particles as well as the corresponding electrochemical properties were investigated. Rutile TiO₂ was more desirable in acquiring high purity Li₄Ti₅O₁₂ than anatase due to the anatase to rutile phase transformation, which was found to be more rigid in the solid-state reaction than the intact rutile phase. Mechanochemical activation of the starting materials was effective in decreasing the reaction temperature and particle size as well as increasing the Li₄Ti₅O₁₂ content. The specific capacity depended significantly on the Li₄Ti₅O₁₂ content, whereas the rate capability improved with decreasing particle size due to the enhanced contact area and reduced diffusion path. Overall, a 200 nm-sized Li₄Ti₅O₁₂ powder with a specific capacity of 165 mAh/g could be synthesized by optimizing the milling method and starting materials.     

Microstructure of high battery-performance Li2FeSiO4/C composite powder synthesized by combining different carbon sources in spray-freezing/freeze-drying process

Spray-freezing/freeze-drying technique was applied to the synthesis of Li₂FeSiO₄/C composite powders using solutions containing various carbon sources, water-soluble and colloidal carbon, followed by heat treatment. The effects of the carbon sources on the microstructure and battery performance of the synthesized composite powders were investigated. The microstructures of the composite powders were clearly different when different carbon sources were used, ascribed from the thermal behavior of the carbon sources during the heat treatment. It was possible to control the microstructures of Li₂FeSiO₄/C composite powders by combining different carbon sources, and the synthesized composite powders exhibited high discharge capacities by mixing with only a binder for cathode. The composite powders using glucose and Ketjenblack dispersion as carbon sources delivered 165 mAh/g at first discharge capacity at 0.1?C. The developed chain structure suitable for conducting paths in the electrodes and a higher-specific BET surface area, attributed from Ketjenblack, were likely responsible for the higher performance.     

镍电极对Ni/MH电池寿命的影响

电池的循环寿命是电池的主要技术指标之一,影响电池寿命的因素较多,本文就镍电极而言,X光衍射分析表明:电池过充电时,镍正极上产生的γ-NiOOH及电极的不完全可逆性是影响电池寿命的重要因素。