【作者】 李琛；

【导师】 张莉；

【作者基本信息】 大连理工大学 ， 电机与电器， 2013， 博士

【摘要】 超级电容器作为一种新型的储能器件,既具有较大的能量密度和功率密度,同时又具有较长的循环寿命,在新能源发电、脉冲功率电源系统、电动汽车及电能武器等领域得到了广泛的应用。首先,本文以超级电容器为研究对象,根据双电层电容的形成机理,深入研究了电极-溶液界面的结构和性质,探讨了电解液离子在多孔电极及溶液间的分布特点和传递规律。在总结现有超级电容器模型的基础上提出双电层的矩阵式模型,研究了双电层电容器内部电荷、电压的分布规律。同时针对超级电容器电极的特点,根据该模型初步探讨了影响双电层电容器储能的因素和超级电容器的自放电机理。其次,以碳纳米管为基体,研究了碳纳米管分别与活性炭、二氧化锰、聚苯胺组成复合电极材料的电化学性能,着重分析了电极材料组成对电容性能的影响。其中聚苯胺/碳纳米管电极具有较优的电容性能,其比电容为245F·g-1,等效串联电阻(ESR)为0.811Ω。为了提高电极材料的储能特性,本文采用低温氧等离子体改性的方法,对电极材料进行改性处理。通过研究不同的处理时间,对比分析了不同改性深度下电极材料的微观结构和电化学性能。实验结果表明,经过1Omin的改性处理后,各电极材料接枝上了羟基官能团,微观结构更加均匀,阻抗性能得到明显提升。聚苯胺/碳纳米管电极材料的比电容为320F·g-1,为改性前的1.3倍,ESR为0.32ΩΩ,较改性前降低了60.5%；二氧化锰/碳纳米管电极材料的比电容为260.9F·g-,为改性前的1.27倍,ESR为0.35f2,较改性前降低了60.7%。由此证明,氧等离子体改性为超级电容器电极材料的优化制备提供了一定的思路。第三,采用聚氯乙烯作为封装材料,对超级电容器单元进行封装。封装外壳尺寸为φ37mm×10mm的圆柱形,其内部采用堆叠式结构。在此基础上对超级电容器单元和三单元组成的串联模块进行循环充放电试验。结果表明,经1000次循环充放电试验后,其电容保持率最高可达98%。最后,在储能系统、脉冲功率系统及其他高功率的应用场合,由于超级电容器的单体电压较低,通常需要将若干电容器单元串联组成储能模块来满足负载对电源系统电压等级的要求。但由于制造工艺、使用环境等因素会造成串联单元的性能不一致,从而在充电时会使得各串联单体间电压不均衡。故针对此问题,本文设计了基于PIC单片机控制的电压均衡系统,该系统由电压采集单元、控制单元及均衡主电路组成,以实现串联超级电容器组在充电过程中单体间的均衡充电,从而提高储能系统的安全性和效率。实验结果表明,针对10组单体参数为55V、9F电容器串联组成的储能系统,该均衡电路能够实现在0-20A,0-550V范围内的均衡充电。更多还原

【Abstract】 As a novel kind of energy storage component, supercapacitor has high energy density, power density and cycle life. It has a wide application in the fields such as new kinds of electricity generation, pulse power system, electric vehicles and electromagnetism weapons.Firstly, in this paper, the supercapacitor was regarded as the research object. On the basis of the formation mechanism for the double layer capacity, the structure and properties of the electrode-solution was thoroughly studied. At the same time, the distribution and transmission characteristics of ions in the solution were discussed. After a summary of the models for supercapacitor, the matrix model of the double layer capacitor was proposed. On the basis of this mathematical model, the charges and voltage distribution in the inner side of the double layer capacitor was investigated. Meanwhile, the factors that influence the energy storage and self discharge mechanism of the doule layer supercapacitor was also discussed.Secondly, as regard to the field of the supercapacitor electrode, the electrochemical properties of carbon nanotubes (CNT) electrode and actived carbon/carbon nanotubes (AC/CNT) electrode, manganese dioxide/carbon nanotubes (MnO2/CNT) electrode, polyaniline/carbon nanotubes (PANI/CNT) electrode were studied. The influence of the electrode component on the capacitance was deeply investigated, and the PANI/CNT electrode had the best performance, which specific capacitance is245F·g-1, equivalent series resistance (ESR) was0.811Ω. In order to enhance the energy stroage character of the electrode material, the modification based on the oxygen plasma was proposed, and the modification was carried out on the electrode materials. Next, the comparison of different modification time on the electrode materials was investigated, and the results of lOmin modification treatment revealed that the hydroxyl functional group was introduced on the electrode materials, the micro morphology was uniformly distributed. Furthermore, as regard to the electrochemical properties, the impedance of each electrode was improved, the specific capacitance of PANI/CNT and MnO2/CNT electrode were320F·g-1and260.9F·g-1respectively, which were1.3and1.27times of the electrodes before modification. The ESR of PANI/CNT and MnO2/CNT electrode were0.32Ω and0.35Ω, which were reduced by60.5%and60.7%respectively after10min modification. This demonstrates that the plasma modification is suitable to the optimized preparation of the electrode material. Thirdly, the polyvinyl chloride (PVC) was used as the packaging material and the electrodes as prepared were stackingly assembled in the037mm×10mm cylinder PVC package. The charge-discharge tests were conducted. The results revealed that the best capacitance maintaince of the three series connected module was98%after1000cycles.Finally, in the fields of energy storage system, pulsed power system and other high power sources, especially the system based on the supercapacitor, the capacitors need to be series connected in order to fulfill the need of the load due to its low unit voltage. Actually, each unit of the series is inconformity owing to the manufacture technique and operating environment, so the voltage between the units is also imbalanced during the charge process. The voltage balance system based on the PIC microchip unit was designed in this paper in order to solve this problem. The balance system consisted of voltage acquisition unit, controlling unit and main circuit, which in order to achieve the balanced voltage of each unit during the charging process and the maximum efficiency of the energy storage system. As regard to the energy storage system consists of10series connected55V9F supercapacitor module, the experiment results demonstrated that this system could realize the balanced charging in the range of0-20A,0-550V.更多还原