【作者】 郭军；

【导师】 王庆年；

【作者基本信息】 吉林大学 ， 车辆工程， 2012， 硕士

【摘要】 汽车的发展改善了人们的生活，促进了社会的发展。在可持续发展呼声高涨的今天，汽车为可持续交通带来了能源、环保和安全三大挑战，人们逐渐把目光投向了新能源汽车，尤其是混合动力汽车和纯电动汽车，研发技术已日趋成熟并已投入市场运营。随着对混合动力汽车和纯电动汽车研究的深入，车载动力电池也已成为研究热点。当前，车载动力电池主要包括铅酸电池、镍镉、镍氢电池和锂离子电池等二次动力电池。几种动力电池在单体制造工艺研发方面取得了显著成就，它们的比能量和比功率都有明显提升，循环使用寿命也有长足进步，然而，无论是哪种车载动力电池，仍与我们的期望目标存在较大的差距。于是人们开始转向研究如何合理管理和使用电池，希望在电池管理方面取得一定技术突破，来弥补电池技术的不足。电池管理系统已成为电池技术研究的子方向之一，然而电池的循环寿命始终是新能源汽车的发展瓶颈。本文从延长电池组循环寿命出发，对车用锂离子动力电池组及其管理系统进行了深入研究。论文的主要研究内容包括：1.查阅国内外在电池组循环寿命方面的研究进展，得出了电池组循环寿命的主要影响因素：充放电倍率、电池放电深度以及电池单体的均一性。其中，充放电倍率超出了电池组的承受能力和放电深度控制不合理属于滥用电池，电池单体的不一致引起电池组的短板效应，都会严重影响电池组的循环寿命。2.以磷酸铁锂电池为研究对象，根据电池特性建立锂离子电池的非线性等效电路模型，利用电路原理知识分析了该模型在阶跃输入下的动态响应。在此研究结果基础上设计了参数辨识实验，利用数学工具Matlab的拟合工具包Curve Fitting Tool辨识出模型参数，并基于Matlab/Simulink搭建了电池模型仿真平台，通过对实验数据和仿真数据的对比分析，验证了模型选择合理且辨识方法有效。3.对电池管理系统进行了详细功能分析。基于主从分布式拓扑结构设计理念，对电池管理系统进行功能划分，将系统分为多个子控制单元和一个主控制单元。子控制单元负责电池单体的电压采集、温度采集、均衡控制、电池组的总电压采集、总电流采集以及漏电状态检测，主控制单元则主要关注电池组整体的状态信息，比如对电池组荷电状态SOC的估算、根据电池组当前SOC对可充放电电流进行估计、子控制单元的弱电管理、高压电继电器控制、以及与整车其他控制器间的信息交互。依据各控制单元的功能需求选择相应的硬件类型并完成硬件电路设计。4.本着延长电池循环寿命的目的，根据对电池组循环寿命影响因素的分析，重点设计了管理系统的软件部分，包括电池组单体均衡控制以及电池组荷电状态SOC和可充放电电流的实时估算。在电池单体均衡方面提出模组最优原则，将数理统计中的标准差理论应用到均衡控制中，通过改善电池组单体一致性来延长电池组循环寿命；通过精确估算电池组SOC和实时估算可充放电电流，为整车合理使用电池提供依据，避免了对电池的滥用，延长了电池组的循环寿命。5.以容量衰减和欧姆内阻增加为电池组循环寿命的评价指标，对本文设计的电池管理系统进行了台架实验。结果表明，本文的设计能有效延长电池组循环寿命，且SOC估算精度符合国家标准要求。更多还原

【Abstract】 Our lives got improved and social development got promoted with the development ofautomotive. With the trend of sustainable development, auto brings three major challengesfor sustainable transport: energy, environmental and safety problem. Gradually people putthe attention on new energy vehicles, especially on Hybrid Electric Vehicles (HEV) andElectric Vehicles (EV), whose research and development technology are matured and havebeen put into market operations. With the in-depth research on HEV and EV, the powerbattery has also become a hot research topic. At present, the power batteries used on newenergy vehicles mainly includes lead-acid batteries, nickel cadmium, nickel metal hydridebatteries and lithium-ion battery. These power batteries have achieved remarkableachievements in the monomer manufacturing process, their energy density and powerdensity get increased as well as their life cycle. Nevertheless, there is a big gap between ourdesired goals and its performance no matter what power battery it is. For that reason, peoplestart to research how to manage and use battery reasonably, hoping for making sometechnological breakthrough in battery management which can compensate for the lack ofbattery technology. The battery management system has become a sub-direction of thebattery technology. The battery cycle life is always the bottleneck in the development of newenergy vehicles. In view of this circumstance, this paper studied the management system oflithium-ion battery pack deeply for prolonging its life cycle. The main contents of this paperare as following.1. Consult the progress of domestic and foreign in the cycle life of the battery pack,and get the main relevant influence factors of the cycle life of the battery pack: the chargeand discharge rate, the depth of discharge and the homogeneity of the single battery. Chargeand discharge rate exceeds the bearing capacity of the battery pack, the unreasonable controlabout the depth of discharge, are two kinds of battery abuse. Battery monomerinconsistencies would result in the short-board effects of the battery pack. They all affect the life cycle of the battery pack seriously.2. Take iron phosphate lithium battery as the research object, build lithium-ion batterynonlinear equivalent circuit model according to battery features, and make use of circuitschematic knowledge to analyze the dynamic response of the model under the step input.Then design parameters identification experiment on the basis of the results of this study,and use mathematical Curve Fitting Tool of Matlab to identify the model parameters. Build abattery model on the simulation platform Matlab/Simulink, and then verify model selectionreasonable and identification method valid by comparison of experimental data andsimulation data.3. Give a detailed functional analysis on Battery management system, based on thedesign concept of the distributed topology structure, and divide the batterymanagement system into several sub-control units and a main control unit. Sub-controlunit is responsible for the voltage and temperature collecting of battery monomer, balancecontrolling, the total voltage collecting, the total current collecting and leakage detecting, inthe mean time the main control unit is more concerned about the overall states of the batterypack, such as the estimate of SOC, the estimate of charge and discharge current accordingto the SOC, the power supply management of sub-control unit, high-voltage relay control,and the information exchange with other controllers of the vehicle. Then select theappropriate type of hardware based on the functional requirements of the control unit andcomplete the hardware circuit design.4. In order to extend the cycle life of the battery, according to the influence factorsanalysis for the battery pack, the paper design the software part of the BMS, includingmonomer balancing control, real-time estimation for SOC and the available current duringthe charge and discharge. Come up with the most optimization principle in the aspect ofmonomer balancing, and add the standard deviation theory into the balance controllingalgorithm, so we can extend the battery cycle life by improving the monomer consistence ofbattery pack. By estimating the SOC and the available current of charge and discharge, wecould avoid the abuse of the battery in order to extend its cycle life. 5. According to the bench test which is used to verify the BMS designed in the paper,we can prove that the design can extend the cycle life of the battery pack effectively by theevaluations of capacity attenuation and ohm resistance increasing.更多还原