基于极化电压特性锂电池优化充电研究

发布时间：2018-08-17 16:33

【摘要】：摘要：本论文结合锂电池充电基本特性和优化充电指标,以单体电池作为研究对象,提出一条基于极化电压特性的优化充电曲线,并考虑了温度的影响。首先研究了锂电池在不同充电倍率、不同充电恒压点条件下的充电时间、充电容量、恒流恒压阶段比例、内阻等因素。针对恒压阶段充电时间不易计算的问题,研究了不同倍率充电条件下恒压转折点的规律,修正了锂电池CC-CV充电时间的计算公式。重点研究了锂电池的极化电压特性,包括极化电压时间常数特性、极化电压倍率特性、极化电压SOC区间特性、极化电压动态特性。把时间常数分解为两数量级与锂离子反应过程对应；建立极化电压倍率线性模型,提出极化倍率系数的概念；分析了极化电压SOC区间特性的原因；发现并拟合分析了极化电压动态特性包括滞后效应和超调效应。给出了在全SOC区间的极化电压模型。进而基于极化电压模型,综合考虑提高充电速度降低充电极化,提出以时间常数作为充电时间长度,以极化电压作为限制的极化电压充电曲线。在不同内阻,不同时间常数,不同端电压因素下做了仿真,并与实验数据对比验证。利用充电实验平台设计了充电验证实验。最后考虑充电过程中的温升,对充电曲线做了补充,基于实验数据和电池质点模型仿真分析了不同充电倍率、不同充电起始SOC的电池温升变化。以充电温升作为限制修正补充了充电边界曲线。基于极化电压的边界充电曲线和考虑温升的边界充电曲线,提出了以充电容量和充电时间作为优化目标和以充电时间和控制电池温升为优化目标两种优化充电策略,并进行仿真分析和实验验证。
[Abstract]:Absrtact: based on the basic characteristics of lithium battery charging and the optimized charging index, this paper presents an optimized charging curve based on polarization voltage characteristics and takes the effect of temperature into account. The factors such as charging time, charging capacity, proportion of constant current and constant voltage, internal resistance of lithium battery under different charging rate and constant voltage point were studied. In order to solve the problem that the charging time in constant voltage stage is not easy to calculate, the rule of constant voltage turning point under different rate charging conditions is studied, and the formula for calculating CC-CV charging time of lithium battery is revised. The characteristics of polarization voltage of lithium battery, including polarization voltage time constant, polarization voltage rate, polarization voltage SOC interval characteristic and polarization voltage dynamic characteristic, are studied in detail. The time constant is decomposed into two orders of magnitude corresponding to the reaction process of lithium ion, the linear model of polarization voltage rate is established, the concept of polarization rate coefficient is put forward, and the reason of the characteristic of polarization voltage SOC region is analyzed. The dynamic characteristics of polarization voltage including hysteresis effect and overshoot effect are found and analyzed. The polarization voltage model in the whole SOC region is given. Based on the polarization voltage model, the charging curve with the time constant as the charging time and the polarization voltage as the limit is proposed, considering comprehensively increasing the charging speed and reducing the charge polarization. The simulation results are compared with the experimental data under different internal resistance, different time constants and different terminal voltage factors. The charging verification experiment is designed by using the charging experiment platform. Finally, considering the temperature rise in the charging process, the charging curve is supplemented. Based on the experimental data and the battery particle model, the temperature rise of the battery with different charging rates and different charging initiation SOC is simulated and analyzed. The charging boundary curve is supplemented by charging temperature rise as a limit correction. Based on the boundary charging curve of polarization voltage and the boundary charging curve considering temperature rise, two optimal charging strategies are proposed, which are the optimal charging capacity and the charging time, and the charging time and controlling the temperature rise of the battery. Simulation analysis and experimental verification are carried out.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

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