锂离子动力电池容量估算方法的研究

发布时间：2018-06-06 03:00

本文选题：锂离子电池 + 容量估算　；参考：《哈尔滨工业大学》2016年硕士论文

【摘要】：随着电动汽车的逐步推广以及锂离子动力电池的快速发展。对动力电池性能的检测变得尤为重要。容量是电池最主要的性能参数,随着锂离子电池的循环工作,电池内部会发生老化现象,动力电池实际总容量也随之衰减,降低了电动汽车的续航能力。针对传统流程繁杂的电池容量检测方法,本文利用锂离子电池充电曲线与电池老化程度的对应关系,提出了一种对动力锂离子电池实际总容量进行快速且准确的检测方法。本文将恒流充电充入的容量作为锂离子电池实际总容量,通过曲线拟合的方式将离散数据连续化,并对多项式拟合与高斯拟合的拟合效果做了比对,分析表明高斯函数更适用于电化学过程的拟合。利用凹凸性分析了充电曲线平台拐点特性,提出利用三阶导数极大值信息获得得曲线拐点位置的方法。采用一阶微分曲线的单调性验证了恒流充电各反应阶段的均匀性,提出了利用直线拟合恒流充电各反应阶段电压曲线的方法。利用对锂离子电池循环充电数据进行等间隔取样的方法,统计了各拐点位置与各反应阶段斜率随电池老化的变化趋势,认为各拐点与各阶段斜率随电池使用变化均匀。设计了通过直线拟合恒流充电各反应阶段的容量估算方案,对磷酸铁锂电池与三元锂离子电池不同容量状态下电池完整的恒流充电时间进行了估算实验,进而得到对应状态下的电池估算容量。通过估算误差的样本概率分布,探讨了估算方案对电池使用阶段的适用条件。分析了不同充电倍率、环境境温度及数据采样率对恒流充电曲线造成的影响,提出了估算方案适用的数据测试条件。针对动力电池实际使用中出现的数据缺失情况,设计了通过历史数据段弥补缺失数据的估算方案,并指出了方案存在的不足。
[Abstract]:With the gradual promotion of electric vehicles and the rapid development of lithium ion power battery. It is very important to test the performance of power battery. Capacity is the most important performance parameter of battery. With the cycle of Li-ion battery, aging will occur inside the battery, and the actual total capacity of power battery will also decrease, which reduces the ability of electric vehicle to live. Aiming at the traditional measurement method of battery capacity, a rapid and accurate method for measuring the actual total capacity of power lithium-ion battery is proposed by using the relationship between the charging curve of lithium ion battery and the aging degree of the battery. In this paper, the capacity of constant current charging is taken as the actual total capacity of lithium-ion battery, the discrete data is continuous by curve fitting, and the fitting effect of polynomial fitting and Gao Si fitting is compared. The analysis shows that the Gao Si function is more suitable for the fitting of electrochemical processes. The inflection point characteristics of charging curve platform are analyzed by using convexity, and the method of obtaining the inflection point position of the curve by using the maximum information of third order derivative is put forward. The monotonicity of the first order differential curve is used to verify the uniformity of each reaction stage of constant current charging, and a method of fitting the voltage curve of each reaction stage of constant current charging by using straight line is put forward. By sampling the charging data of lithium ion battery at equal intervals, the tendency of the change of the inflection point position and the slope of each reaction stage with the aging of the battery is calculated. It is considered that the slope of each inflection point and stage varies uniformly with the use of the battery. A method for estimating the capacity of lithium iron phosphate battery and ternary lithium ion battery is designed by fitting the capacity of each reaction stage of constant current charging. The complete constant current charging time of lithium iron phosphate battery and ternary lithium ion battery is estimated. Then the estimated capacity of the battery in the corresponding state is obtained. Through the sample probability distribution of the estimation error, the suitable conditions of the estimation scheme for the battery operation stage are discussed. The influence of different charging rate, ambient temperature and data sampling rate on the constant current charging curve is analyzed, and the data test conditions applicable to the estimation scheme are put forward. In view of the lack of data in practical use of power battery, an estimation scheme of compensating missing data by historical data segment is designed, and the shortcomings of the scheme are pointed out.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM912;U469.72

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