高比能锂离子电池研制及性能研究
发布时间：2019-03-09 19:12
【摘要】：近年来,供电系统对电源的轻量化要求日益突出。锂离子电池由于具有比能量高、循环寿命长等优势,已逐渐成为诸多供电系统的首选储能电源。但是,目前国内储能电源应用较为成熟且工程化的LiCoO_2/LiC_6体系锂离子电池,其比能量在110Wh/kg~130Wh/kg之间,无法满足高比能锂离子电池的使用要求。本论文针对工程应用的实际需求,同时适应高倍率充放电和宽温度范围工作的任务特点,重点对影响电池比能量和综合性能的正极、负极和电极液三个部分进行了研究。依托试验结果研制了高比能量锂离子电池,对电池的性能和安全性进行了测试,并对电池的性能特点和循环性能进行了验证、分析和总结。锂离子电池的设计与其充放电模式、工作温度和工作寿命等使用要求密切相关。高性能电极材料在锂离子电池中起着举足轻重的作用,是提高电池比能量的重要途径。相比于锂离子电池普遍采用的LiCoO_2材料,LiNi_XCo_yAl_ZO_2材料表现出更为优异的比容量、热稳定性和高温性能,且性能成熟稳定,是理想的高比能量锂离子电池正极材料。本论文还研究了正极导电剂种类和含量,以及电极压实密度对电极性能的影响。SP、SFG和VGCF三种不同类型的导电剂混合使用的效果最佳;为达到比能量最优,导电剂的含量和电极的压实密度均存在最佳值。对负极石墨材料的形貌和粒度对电极性能的影响进行了研究。相较于SEM形貌为无规则和长椭圆形的石墨材料,球形石墨制备的电极的浸润时间最短,制备的电池的交流阻抗最小;粒度大的石墨材料较粒度小的浸透速率大。因此,大粒径球形石墨负极材料表现出更为优异的比能量和倍率性能。本论文还通过电解液与电极的相容性,电池的交流阻抗值,电池在不同工作温度下的放电容量和放电电压,以及充放电循环性能,对三种不同型号电解液的匹配性进行了研究。B型电解液电池在上述四方面的性能均优于其他两种电解液电池。本论文研制了高比能量锂离子电池,测试结果表明:比能量较LiCO_2电池显著提高,达到170.35Wh/kg(0.5CA,4.1V);-20℃容量为20℃容量的82.5%,放电容量随温度的升高而升高,50℃容量约为20℃容量的110%,表现出良好的温度特性。电池按照工作模式循环1235次后的放电电压未见明显衰降,容量保持率为93.73%,循环性能优异。研制的高比能锂离子电池性能满足工程应用要求并具有广阔的应用前景。
[Abstract]:In recent years, the demand for lightweight power supply in power supply system is becoming more and more prominent. Due to its advantages of high specific energy and long cycle life, Li-ion battery has gradually become the first choice of energy storage power supply for many power supply systems. However, the specific energy of LiCoO_2/LiC_6 lithium-ion battery is between 110Wh/kg~130Wh/kg and can not meet the requirements of high-specific-energy lithium-ion battery because of its mature application and engineering application. According to the practical requirements of engineering application and the task characteristics of high-rate charge-discharge and wide temperature range, the positive, negative and liquid electrodes which affect the specific energy and comprehensive performance of the battery are studied in this paper. A lithium ion battery with high specific energy was developed on the basis of the experimental results. The performance and safety of the battery were tested, and the performance characteristics and cycle performance of the battery were verified, analyzed and summarized. The design of Li-ion battery is closely related to its charge-discharge mode, working temperature and service life. High performance electrode material plays an important role in lithium ion battery and is an important way to improve the specific energy of the battery. Compared with the LiCoO_2 materials commonly used in lithium ion batteries, LiNi_XCo_yAl_ZO_2 materials show better specific capacity, thermal stability and high temperature performance, and the properties are mature and stable. It is an ideal cathode material for lithium ion battery with high specific energy. The types and contents of cathode conductive agents and the effect of electrode compaction density on electrode performance were also studied in this paper. Three different types of conductive agents, SP, SFG and VGCF, were used in the best effect. In order to achieve the optimal specific energy, the content of the conductive agent and the compaction density of the electrode have the best value. The effects of morphology and particle size of negative graphite materials on the electrode properties were studied. Compared with the irregular and long ellipsoidal graphite materials with SEM morphology, the electrode prepared by spherical graphite has the shortest infiltration time, and the AC impedance of the prepared battery is the smallest, and the graphite material with large particle size is larger than the impregnated rate with smaller particle size. Therefore, the large particle size spherical graphite anode materials show more excellent specific energy and ratio properties. In this paper, the compatibility between electrolyte and electrode, AC impedance, discharge capacity and voltage at different operating temperatures, and charge-discharge cycle performance are also studied. The matching properties of three different types of electrolyte were studied. The performance of type B electrolyte battery was better than that of the other two electrolyte batteries in the above four aspects. In this paper, a lithium ion battery with high specific energy has been developed. The test results show that the specific energy of lithium ion battery is significantly higher than that of LiCO_2 battery, reaching to 170.35Wh/kg (0.5A, 4.1V). The capacity at-20 鈩，
本文编号：2437770
[Abstract]:In recent years, the demand for lightweight power supply in power supply system is becoming more and more prominent. Due to its advantages of high specific energy and long cycle life, Li-ion battery has gradually become the first choice of energy storage power supply for many power supply systems. However, the specific energy of LiCoO_2/LiC_6 lithium-ion battery is between 110Wh/kg~130Wh/kg and can not meet the requirements of high-specific-energy lithium-ion battery because of its mature application and engineering application. According to the practical requirements of engineering application and the task characteristics of high-rate charge-discharge and wide temperature range, the positive, negative and liquid electrodes which affect the specific energy and comprehensive performance of the battery are studied in this paper. A lithium ion battery with high specific energy was developed on the basis of the experimental results. The performance and safety of the battery were tested, and the performance characteristics and cycle performance of the battery were verified, analyzed and summarized. The design of Li-ion battery is closely related to its charge-discharge mode, working temperature and service life. High performance electrode material plays an important role in lithium ion battery and is an important way to improve the specific energy of the battery. Compared with the LiCoO_2 materials commonly used in lithium ion batteries, LiNi_XCo_yAl_ZO_2 materials show better specific capacity, thermal stability and high temperature performance, and the properties are mature and stable. It is an ideal cathode material for lithium ion battery with high specific energy. The types and contents of cathode conductive agents and the effect of electrode compaction density on electrode performance were also studied in this paper. Three different types of conductive agents, SP, SFG and VGCF, were used in the best effect. In order to achieve the optimal specific energy, the content of the conductive agent and the compaction density of the electrode have the best value. The effects of morphology and particle size of negative graphite materials on the electrode properties were studied. Compared with the irregular and long ellipsoidal graphite materials with SEM morphology, the electrode prepared by spherical graphite has the shortest infiltration time, and the AC impedance of the prepared battery is the smallest, and the graphite material with large particle size is larger than the impregnated rate with smaller particle size. Therefore, the large particle size spherical graphite anode materials show more excellent specific energy and ratio properties. In this paper, the compatibility between electrolyte and electrode, AC impedance, discharge capacity and voltage at different operating temperatures, and charge-discharge cycle performance are also studied. The matching properties of three different types of electrolyte were studied. The performance of type B electrolyte battery was better than that of the other two electrolyte batteries in the above four aspects. In this paper, a lithium ion battery with high specific energy has been developed. The test results show that the specific energy of lithium ion battery is significantly higher than that of LiCO_2 battery, reaching to 170.35Wh/kg (0.5A, 4.1V). The capacity at-20 鈩，
本文编号：2437770
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