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电动车用铅酸蓄电池二氧化铅电极的研究
Studies on the PbO2 Electrode of Lead/Acid Batteries for Electric Vehicles
【作者】 李建玲;
【作者基本信息】 哈尔滨工业大学 , 环境化工, 1998, 博士
【摘要】 为了保护环境,节约能源,电动车的发展势在必行。阀控式铅酸蓄电池以其优良的性能价格比成为近期及过渡时期电动车用动力电源的理想选择,因此对铅蓄电池的控制电极一二氧化铅(PbO2)电极的研究对提高铅蓄电池性能,促进铅蓄电池在电动车上的应用具有重要的意义。本文综述了PbO2电极的发展研究概况,分析了PbO2电极存在的主要问题,从板栅合金和正极活性物质(PAM)的性质变化着手,在基础理论和应用方面对PbO2电极进行了系统深入的研究,以提高对PbO2电极活性物质微观结构的再认识,改善PbO2电极性能。 本文系统地研究了Bi对Pb—Ca合金腐蚀行为的影响。Bi通常作为杂质存在于铅中,Bi的去除过程非常困难,因此Bi对板栅合金及PbO2电极性能的影响引起人们极大的关注。通过恒电流阳极失重法,扫描电镜(SEM)观察,腐蚀电阻测定及充放电循环实验,得出在Bi含量为0.0025—0.0648wt.%范围内,随Bi含量增加,Pb—Ca—Sn—Al合金耐蚀性能提高,同时Bi对PbO2电极充放循环特性具有良好影响。 在对一些无机及有机添加剂进行筛选的基础上,采用扫描电镜(SEM)观察、X射线衍射(XRD)、差热—热重(DTA—TG)分析和X射线光电子能谱(XPS)等方法对失效电极中正极活性物质形貌及有关特性进行了研究,探讨了影响PbO2电极的两种失效机理,即含添加剂A的电极(容量一般,寿命较长)失效是由于PbO2由电化学活性变为非电化学活性引起的;含紫脲酸胺和添加剂B的电极(容量高,寿命较短)失效是由于PbO2粒子间失去导电联系而引起容量损失、寿命终止的。XPS分析表明,添加剂对PbO2电极的作用并非是通过增加凝胶区水含量而实现的。 开发出两种新型的正极活性物质添加剂B和A,研究了复合添加剂(B+A)对PbO2电极性能的影响。B具有提高电极容量的作用,良好作用表现在前、中期;A具有延长循环寿命的作用,良好作用表现在中、后期。B和A的联合使用使电极显示了优良性能,中高倍率(3h率)放电容量可提高8—15%,寿命延长7%。
【Abstract】 The development of electric vehicles(EV) is imperative in order to protect environment and save energy. In the interim and near future the most promising candidate of power sources for EV is a certain type of valve—regulated lead/acid (VR-LA) batteries due to their high performance — cost ratio. Therefore, studies of PbO2 electrode as the performance determining electrode of lead/acid batteries are of great importance to improve their performance and applications to EV. Recent researches on PbO2 electrodes were reviewed and the main problems arising were analysed in this dissertation. It started with positive grid alloys and the property change of positive active materials (PAM), made a systematic and thorough study on PbO2 electrodes in the respect of basic theories and applications to deepen our understanding of microstructure of their PAM and improve their performance.The influences of bismuth on the corrosion behavior of Pb — Ca alloys were systematically studied. Bismuth is usually present in metallic lead as an impurity, and debismuthising of lead is difficult. Consequently, the effect of residual bismuth on the performance of grids and PbO2 electrodes has been the matter of great interest. Experimental results from the weight loss by constant current polarization, SEM observation, corrosion resistance determination and charge — discharge cycling showed that the corrosion — resistivity of Pb — Ca — Sn — Al alloys were increased with the increase of bismuth content in the range of 0. 0025 — 0. 0648 wt. %, and bismuth presented good effect on the cycling performance of PbO2 electrodes.On the basis of screening some inorganic and organic additives, the morphology and some related characteristics of PAM from the failed positive plates were examined by SEM observation, XRD, DTA — TG and XPS. Two failure mechanisms of PbO2 electrodes were proposed, namely, the failure of the electrodes with additive A (with ordinary capacity and longer cycle life) was due to the conversion
【Key words】 Electric Vehicles; Lead/Acid Batteries; PbO2 Electrode; Additive; Microstructure;