循环式充电放电锂电池电化学特性研究

发布时间：2018-10-21 18:11

【摘要】：循环式充电放电锂离子电池是目前常用的动力用锂离子电池,其具有能量密度大、结构简单、安装更换方便等技术及结构优点,目前已经成为纯电动汽车及混合动力汽车的电力供给设备首选。在充电及放电过程中,多种化学反应、电化学反应及物质传输过程同时发生,对锂离子电池的安全性及工作稳定性的研究相继开展。在掌握了理论基础及应用软件平台的前提下,根据以往实验数据进行模拟仿真计算,对循环式锂离子电池充电放电进行了详细的电化学研究,论文使用CFD仿真研究手段对循环式锂离子电池的充电放电过程的电压特性、电解质浓度趋势、电流密度分布及颗粒扩散规律等分别开展了一维、二维电化学模拟研究,对锂离子电池的正负极材料选取及相关动力用电池产品改进提供相关的理论指导。论文主要研究工作如下:(1)参照相关实验及理论研究结果,采用一维Newman模型对循环式充电放电锂离子电池的电压特性、压降损耗及电流密度分布进行了模拟计算,电化学特性结果与锂电池实际应用过程相符合;(2)采用CFD电化学二次程序对循环式充电放电锂离子电池进行了二维模拟计算,进一步得出正负极材料的扩散趋势、颗粒浓度变化等规律,对锂离子电池的正负极材料选取及相关动力用电池产品改进提供相关的理论指导;(3)采用数据耦合的方式将锂电池电化学模型与热模型相互结合,得出了电化学-热耦合模型下的锂电池温度分布趋势,电解质浓度扩散规律等相关结论。进一步加深对锂离子电池产热及散热起因和过程的理解,为锂离子电池的安全性提高提供参考。
[Abstract]:The circulating charge discharge lithium ion battery is a commonly used power lithium ion battery at present. It has the advantages of high energy density, simple structure, convenient installation and replacement, etc. At present, it has become the first choice of power supply equipment for pure electric vehicles and hybrid electric vehicles. During charging and discharging, a variety of chemical reactions, electrochemical reactions and mass transfer processes occur simultaneously. The research on the safety and working stability of lithium-ion batteries has been carried out one after another. On the premise of mastering the theoretical foundation and the application software platform, the charge discharge of circulating lithium ion battery is studied in detail according to the simulation and calculation of the previous experimental data. In this paper, the voltage characteristics, electrolyte concentration trend, current density distribution and particle diffusion law of rechargeable lithium ion battery are studied by CFD simulation. It provides theoretical guidance for the selection of cathode materials and the improvement of battery products for lithium ion batteries. The main work of this paper is as follows: (1) according to the experimental and theoretical results, the voltage characteristics, voltage drop loss and current density distribution of rechargeable Li-ion battery are simulated by one-dimensional Newman model. The results of electrochemical characteristics are in agreement with the practical application process of lithium battery. (2) Two-dimensional simulation of cyclic charge discharge lithium ion battery is carried out by using CFD electrochemical secondary program, and the diffusion trend of positive and negative electrode materials is further obtained. The change of particle concentration provides relevant theoretical guidance for the selection of cathode materials for lithium ion batteries and the improvement of related power battery products. (3) the electrochemical model and thermal model of lithium ion battery are combined with each other by data coupling. The temperature distribution trend and electrolyte concentration diffusion law of lithium battery under the electrochemical-thermal coupling model were obtained. Further understanding of the cause and process of heat production and heat dissipation of lithium-ion batteries provides a reference for improving the safety of lithium-ion batteries.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM912

【相似文献】