由于锂离子电池具有能量密度高、循环寿命长且自放电率低等优点，被作为电化学能源系统在电动汽车领域广泛应用。为满足电动汽车的功率需求，单体锂离子电池需要串并联成组使用，成组后由于单体电池的不一致性，导致电池组寿命加速衰减甚至出现安全隐患。为实现车载锂离子电池组的均衡管理，改善其单体电池的不一致性问题。本文从电池等效电路模型构建、均衡拓扑结构改进、均衡控制策略设计及均衡实验平台搭建展开研究。具体研究内容如下：

（1）建立电池的等效电路模型，并辨识其内部参数，采用Simulink对所搭建二阶RC等效电路模型进行仿真，获取锂离子电池电压仿真结果。将模型仿真电压与实验测试电压进行对比，验证所搭建模型的准确性。基于所搭建电池模型，采用扩展卡尔曼滤波算法来估计电池的荷电状态（State of Charge，SOC），将仿真结果与实验数据进行对比，两者的最大误差在4.2%以内，验证所提方法的有效性。

（2）提出一种闭环分层式改进型Buck-Boost均衡拓扑结构，来弥补传统型Buck-Boost拓扑结构均衡效率低的不足。并在Simulink中对两种拓扑结构以相同的均衡控制策略进行仿真，仿真结果表明改进型Buck-Boost均衡拓扑在充电、放电和静置三种工况下的均衡效率均优于传统型，验证所设计均衡拓扑结构的可行性。

（3）提出一种基于模糊控制逻辑的电池组均衡控制策略，以电池的SOC值作为均衡变量，动态调整均衡电流的大小。利用Simulink进行仿真，仿真结果表明，该均衡控制策略可根据电池组工作状态实现均衡电流的动态调整，提高均衡系统的均衡效率。

（4）搭建电池均衡系统实验平台，根据电池均衡系统的功能需求，设计其硬件电路及软件程序。对六块串联电池组进行各工况下的均衡实验，结果表明设计的电池均衡系统有效减小了电池组的不一致性，提升了锂离子电池组的均衡效率。

Lithium-ion battery is widely used as electrochemical energy systems in electric vehicles due to their high energy density, long cycle life, and low self-discharge rate. To meet the power demand of electric vehicles, single lithium-ion batteries need to be connected in series and parallel to form a group, and the inconsistency of single batteries after forming a group leads to accelerated degradation of the battery pack life and even potential safety hazards. In order to realize the balanced management of automotive lithium-ion battery packs, and improve the inconsistency of single battery. In this dissertation, the research is carried out from the construction of a battery equivalent circuit model, the improvement of equalization topology, the design of an equalization control strategy, and the construction of an equalization experimental platform. The specific research content is as follows:

(1) The equivalent circuit model of the battery is established and its internal parameters are identified, and the second-order RC equivalent circuit model is simulated using Simulink to obtain the simulation results of the lithium-ion battery voltage. The simulated voltage of the model is compared with the experimental test voltage to verify the accuracy of the model. Based on the constructed battery model, the extended Kalman filter algorithm is used to estimate the state of charge (SOC) of the battery, and the simulation results are compared with the experimental data, and the maximum error of the two is within 4.2%, which verifies the effectiveness of the proposed method.

(2) A closed-loop hierarchical improved Buck-Boost equalization topology is proposed to compensate for the low equalization efficiency of the traditional Buck-Boost topology. The two topologies are simulated in Simulink with the same equalization control strategy, and the simulation results show that the equalization efficiency of the improved Buck-Boost equalization topology is better than that of the traditional one under the charging, discharging, and resting conditions, which verifies the feasibility of the designed equalization topology.

(3) A battery pack equalization control strategy based on fuzzy control logic is proposed to dynamically adjust the size of the equalization current with the SOC value of the battery as the equalization variable. Simulation is carried out using Simulink, and the simulation results show that the equalization control strategy can realize the dynamic adjustment of the equalization current according to the working state of the battery pack and improve the equalization efficiency of the equalization system.

(4) The experimental platform for the battery equalization system is built, and the hardware circuit and software program is designed according to the functional requirements of the battery equalization system. Six series-connected battery packs were subjected to equalization experiments under various working conditions, and the results show that the designed battery equalization system effectively reduces the inconsistency of the battery packs and improves the equalization efficiency of lithium-ion battery packs.

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