为应对日益突出的燃油供求矛盾和环境污染问题，国家陆续发布了一系支持、鼓励发展新能源汽车的产业规划和政策。在新能源汽车发展中纯电动汽车又是主要发展方向。动力电池作为纯电动汽车的核心零件，由于整车的高续航性能要求，高能量密度的三元锂离子电池被广泛应用于动力电池领域。然而锂离子电池本身的电化学体系所决定的其最佳工作温度范围在25~35℃之间。因此开发一个智能高效的电池热管理系统，是各个主机厂需要重点研发和突破的技术问题，以提高电池的充放电性能，延长使用寿命，给客户带来更好的驾驶及使用体验。现阶段常用的电池热管理系统解决方案较多而且效果有待改善。但是如果首先能够基于电池单体发热机理构建高精度电池产热模型，并以单体模型为基础结合三维流体分析软件构建的三维电池包热仿真模型，描述电池系统中热场分布，表征系统内热传输机理，是开发设计高效的电池热管理系统关键路径和有效方法。本文基于对方形电芯的热物性模型参数识别和混合脉冲功率性能测试参数建立了方形锂离子单体发热模型，并以此为基础完成了基于STAR CCM+、BDS、BSM和GT-SUITE仿真软件的联合建模，结合整车搭载实测效果对热管理模型进行了验证和标定，形成切实可行的纯电动汽车电池包与整车的热管理仿真分析与计算方法，极具工程意义。本文主要的研究内容和结论如下：利用HPPC测试数据导入到BDS软件模块中，建立电芯发热模型，在STAR CCM+的BSM模块中导入BDS电芯模型，同时设置完整的电池包模型，进行电池包的电化学和热流场的耦合分析，并进行了仿真测试与试验对标，说明所设计的电池包热模型较为合理和精确地反应动力电池组发热特性，也间接验证了所构建的单体热模型的正确性，为后续整车级别热管理模型的搭建奠定了的基础。利用GT-SUITE软件搭建了电池的物理模型和热模型，并通过与三维仿真结果对比标定，构建了同时满足计算精度和计算速度的电池模型。为仿真计算车辆的动力经济性，搭建了车辆行驶系统与热管理系统耦合仿真模型，并对模型进行了仿真测试。使用搭建的电动汽车热管理系统模型进行了工况仿真及相应的试验对比，验证了仿真的模型精度。并在此基础上，以缩短高温、低温快充时间、提高极限温度下续驶里程为目标，提出若干优化方案，并通过仿真模型进行验证。
To cope with the disparities between fuel supply and demand, as well as the environmental pollution, the state has issued a series plans and policies to support the development of pure electric vehicles. High energy density NCM lithium ion batteries are the key parts of electric vehicles, and they are widely used in the field of power batteries because of high endurance performance requirements of the whole vehicle. However, the optimal operating temperature range of lithium ion itself is between 25 and 35 ° C due to its electrochemical system. Therefore, the development of an intelligent and efficient battery thermal management system is a technical problem that needs to be solved by various OEMs, in order to improve the battery's charge and discharge performance, extend its service life, and bring a better driving and use experience to the customers.At this stage, there are many battery thermal management system solutions that need to be improved. However, building a high-precision battery heat generation model based on the battery cell heating mechanism, analyzing the three-dimensional battery package thermal simulation model that is based on the single-model model, describing the thermal field distribution in the battery system, and characterizing the heat transfer mechanism in the system is a critical path and effective method for efficient battery thermal management systems. This paper establishes a module square lithium ion monomer heating model based on the thermal property model parameter identification and hybrid pulse power performance test parameters of square cells. Moreover, the joint modeling based on STRA CCM+, BDS, BSM and GT-SUITE simulation software is completed, the thermal management model is verified and calibrated with the actual measurement results. A practical and feasible analysis and calculation method for the thermal management of pure electric vehicle battery packs and complete vehicles is formed. The main research contents and conclusions of this paper are as follows:The HPPC test data is imported into the BDS software module to establish a cell heating model, and the BDS cell model is introduced into the BSM module of the STRA CCM+. At the same time, a complete battery pack model is set up, and the electrochemical and thermal flow field coupling analysis of the battery pack is performed, and the simulation test and test benchmarking are performed. The research above proves that the designed battery pack thermal model is more reasonable and accurate to reflect the heating characteristics of the power battery pack. It also indirectly verifies the correctness of the constructed single thermal model and lays a foundation for the subsequent vehicle-level thermal management model.The physical model and thermal model of the battery are built by using GT-SUITE software, and the battery model which satisfies the calculation accuracy and calculation speed is constructed by comparing and calibrating with the 3D simulation results. In order to simulate and calculate the power economy of the vehicle, a coupled simulation model of the vehicle driving system and the thermal management system is built, and the model is simulated and tested.The simulation of the working condition and the corresponding test comparison are carried out using the built electric vehicle thermal management system model, and the accuracy of the simulated model is verified. On the basis of this, in order to shorten the high temperature, low temperature fast charge time and increase the driving range under the limit temperature, several optimization schemes are proposed and verified by simulation model.
