【作者】 易四勇；

【导师】 王先友；

【作者基本信息】 湘潭大学 ， 物理化学， 2009， 硕士

【摘要】 锂二次电池作为一种新型清洁、可再生的二次能源,由于其具有工作电压高、能量密度大、自放电小、循环特性好等优点,是手机、笔记本电脑、数码相机等移动式电子设备的理想选择,并逐步向电动汽车、混合型电动汽车和高效储能系统等领域拓展。一场关于汽车能源改革的科技大战正在酝酿。电动汽车的研究、开发、乃至产业化成为全世界关注的问题。而制约新能源汽车发展的最大瓶颈就是电池。本论文研究了锂离子动力电池的制造工艺,对工艺研究中出现的技术难点进行了深入分析。重点研究了混料配方、容量平衡系数、正负极压实密度、电解液添加量和化成制度对锂离子动力电池的性能影响。探讨了额定容量为20Ah的4860110型成品锂离子动力电池的电化学性能和安全性能。通过研究正极活性物质的含量与电池放电容量、内阻及循环容量保持率的关系,确定了正极材料中活性物质的最佳质量百分数为92%。根据电池实际生产的工序能力,考虑电池的放电容量及电池的安全性能,得出动力电池最佳设计容量平衡系数为1.10～1.15。根据生产中装配情况、以及电池的放电容量和倍率放电性能,得到正负极极片的最佳压实密度。锰酸锂材料的最佳压实密度2.7g·cm^-3,石墨的最佳压实密度1.55g·cm^-3。同时,得出电池适宜的装配松紧度为92%～95%。通过研究电池容量、内阻与电解液添加量的关系,以及不同电解液添加量的电池的容量分布情况,确定了电池的电解液添加量为4.0g·Ah^-1。通过研究化成制度对电池容量、电池内阻、充放电效率及电池循环性能的影响,确定化成制度为0.05C充电2h,转0.1C充电至3.95V。在此制度下,能使电池得到较好的活化,并且能够有效降低气胀对电池性能的影响。对4860110型锂离子动力电池进行性能检测,0.2C、0.5C、1C等倍率放电容量均在20Ah以上,1.5C倍率的放电比功率达140 W·kg^-1,比能量达91.5 Wh·kg^-1,以0.3C（6A）循环180次后容量保持率约为91.6%、荷电保持及容量恢复能力及安全性能都达到或超过了QC-T 743-2006电动汽车用锂离子蓄电池标准的要求,适合做电动车用动力电源。更多还原

【Abstract】 Lithium secondary batteries are the new types of cleanliness and recyclable power source.In comparison with conventional battery systems,Li-ion battery possesses intrinsic advantages of high voltage,high energy density,low self-discharge rate and long cyclic life,and is now considered as the competitive power sources for portable electronic equipment,such as communication device,computer and digital electronic products,et al.and then develop toward electric vehicles,hybrid electric vehicles and high-efficient energy storage systems.A big science and technology battle about the innovation of automobile energy resources is brewing.The research, exploitation and industrialization of electric vehicle are becoming the attentive issue in all over the world.The key problem of developing new energy resources vehicle is the batteries.In this paper,the manufacture technology of lithium-ion power battery was introduced,and the difficulties in the technics research were fully studied.The research works focus on the ratio of cathode active material in all cathode materials, balance coefficient of capacity about positive and negative electrodes,compacted density of positive and negative electrode materials,electrolyte content and formation process.At the same time,the electrochemical performance and the safety of 4860110 type lithium ion power battery were studied in detail.The effects of the ratio of cathode active material in all cathode materials on discharge capacity,internal resistance and the capacity retention ratio after cycles were studied,the results showed that the optimal ratio of active material was 92wt.%.According to the process ability of practical production,it has been found that the optimal balance coefficient of capacity is in the range of 1.10 to 1.15 based on the discharge capacity and safety performance of power lithium ion battery.Considering the discharge capacity and rate discharge ability of power lithium ion battery,the optimal process condition is suggested that the compacted density of LiMn₂O₄ is 2.7 g·cm^-3,the compacted density of graphite is 1.55 g·cm^-3 and assembly space is 92%～95%.The relationship of the discharge capacity,internal resistance and the capacity distribution with different electrolyte content was analyzed and discussed,results showed that the optimal electrolyte content was 4.0 g·Ah^-1. The effects of formation procedure on the discharge capacity,internal resistance, charge-discharge efficiency and cycle performance of battery were studied and the optimal formation procedure consists of a dual-current charging,with 0.05C for 2h followed by 0.1C to 3.95 V.Under this formation procedure,the capacity activation of battery was enhanced and the evolution of gases was reduced.The electrochemical tests of 4860110 type power lithium ion battery showed that discharge capacities at the rates of 0.2C,0.5C and 1C were all beyond 20 Ah,and the output power density is 140 W·kg^-1 and the specific energy is 91.5 Wh·kg^-1 at the rate of 1.5C.Besides,0.3C（6A） discharge capacity retains about 91.6%after 180 cycles. Therefore,the storage capability and safety performance of as-prepared power lithium ion battery are better than the standard of QC-T 743-2006 for electric vehicles.更多还原