【摘要】：近年來(lái),供電系統(tǒng)對(duì)電源的輕量化要求日益突出。鋰離子電池由于具有比能量高、循環(huán)壽命長(zhǎng)等優(yōu)勢(shì),已逐漸成為諸多供電系統(tǒng)的首選儲(chǔ)能電源。但是,目前國(guó)內(nèi)儲(chǔ)能電源應(yīng)用較為成熟且工程化的LiCoO_2/LiC_6體系鋰離子電池,其比能量在110Wh/kg~130Wh/kg之間,無(wú)法滿足高比能鋰離子電池的使用要求。本論文針對(duì)工程應(yīng)用的實(shí)際需求,同時(shí)適應(yīng)高倍率充放電和寬溫度范圍工作的任務(wù)特點(diǎn),重點(diǎn)對(duì)影響電池比能量和綜合性能的正極、負(fù)極和電極液三個(gè)部分進(jìn)行了研究。依托試驗(yàn)結(jié)果研制了高比能量鋰離子電池,對(duì)電池的性能和安全性進(jìn)行了測(cè)試,并對(duì)電池的性能特點(diǎn)和循環(huán)性能進(jìn)行了驗(yàn)證、分析和總結(jié)。鋰離子電池的設(shè)計(jì)與其充放電模式、工作溫度和工作壽命等使用要求密切相關(guān)。高性能電極材料在鋰離子電池中起著舉足輕重的作用,是提高電池比能量的重要途徑。相比于鋰離子電池普遍采用的LiCoO_2材料,LiNi_XCo_yAl_ZO_2材料表現(xiàn)出更為優(yōu)異的比容量、熱穩(wěn)定性和高溫性能,且性能成熟穩(wěn)定,是理想的高比能量鋰離子電池正極材料。本論文還研究了正極導(dǎo)電劑種類和含量,以及電極壓實(shí)密度對(duì)電極性能的影響。SP、SFG和VGCF三種不同類型的導(dǎo)電劑混合使用的效果最佳;為達(dá)到比能量最優(yōu),導(dǎo)電劑的含量和電極的壓實(shí)密度均存在最佳值。對(duì)負(fù)極石墨材料的形貌和粒度對(duì)電極性能的影響進(jìn)行了研究。相較于SEM形貌為無(wú)規(guī)則和長(zhǎng)橢圓形的石墨材料,球形石墨制備的電極的浸潤(rùn)時(shí)間最短,制備的電池的交流阻抗最小;粒度大的石墨材料較粒度小的浸透速率大。因此,大粒徑球形石墨負(fù)極材料表現(xiàn)出更為優(yōu)異的比能量和倍率性能。本論文還通過(guò)電解液與電極的相容性,電池的交流阻抗值,電池在不同工作溫度下的放電容量和放電電壓,以及充放電循環(huán)性能,對(duì)三種不同型號(hào)電解液的匹配性進(jìn)行了研究。B型電解液電池在上述四方面的性能均優(yōu)于其他兩種電解液電池。本論文研制了高比能量鋰離子電池,測(cè)試結(jié)果表明:比能量較LiCO_2電池顯著提高,達(dá)到170.35Wh/kg(0.5CA,4.1V);-20℃容量為20℃容量的82.5%,放電容量隨溫度的升高而升高,50℃容量約為20℃容量的110%,表現(xiàn)出良好的溫度特性。電池按照工作模式循環(huán)1235次后的放電電壓未見(jiàn)明顯衰降,容量保持率為93.73%,循環(huán)性能優(yōu)異。研制的高比能鋰離子電池性能滿足工程應(yīng)用要求并具有廣闊的應(yīng)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，

本文編號(hào)：2437770