【作者】 徐丽；

【导师】 何国庚；

【作者基本信息】 华中科技大学 ， 动力工程， 2021， 硕士

【摘要】 随着经济和城镇化的发展,汽车成为人们出行的首要选择,但是随着石油短缺,而传统燃油汽车会对环境产生污染,大力发展新能源汽车。电动汽车的核心部件为动力电池,而温度是影响动力电池的性能的主要因素,因此需要对动力电池进行热管理。本文对电池进行热管理,而电池会产生热量,所以在满足夏天降温的情况下也能满足冬天加热的情况。考虑到成本以及冷却效果,本文采用液体冷却的方式,对电动大巴电池包的散热系统进行设计和优化。本文分析锂离子电池的物理模型和工作原理,分析锂离子电池的产热以及传热原理,计算锂离子电池的热物性参数以及在不同倍率下的生热速率,为后续仿真操作打下基础;对电动大巴的电池进行几何建模和热模型的建造,利用ANSYS Fluent对电池包进行仿真模拟,并用实验来验证仿真模拟,将实验值和仿真模拟的数据进行对比分析,证明仿真的正确性。本文主要对电池包的散热结构进行设计和优化,使电池包能够满足电池热管理的设计要求,并研究了不同冷却因素对电池包散热效果的影响。本文研究了单个电池包在不同环境温度下和不同充电倍率对电池包的温度的影响。研究表明,充电倍率越高,电池温度越高;环境温度越高,电池的温度越高;对电池包散热模型进行设计,仿真模拟在1C、3C和5C下的电池包温度分布,根据仿真结果对电池包进行结构优化,将单进单出管路改为双进双出管路,同时在侧面放置冷板,并进行结构优化后的电池温度仿真模拟,可以使优化结构后的电池包在工作状态下的温度能满足热设计的要求;对改进结构后的电池包散热模型研究不同冷却因素对电池温度的影响,研究表明,冷却液流量的提高对电池温度几乎没有影响;冷却液温度越低,电池的最高温度也越低,但是过低的冷却液温度会使电池包的温度过低;空气对流换热系数对电池包温度的影响不大。更多还原

【Abstract】 With the development of economy and urbanization,vehicles have become the first choice for people to travel,but with the shortage of oil and the pollution of traditional fuel vehicles to the environment,it is necessary to develop electric vehicles.The core component of electric vehicle is power battery,and temperature is the main factor affecting the performance of power battery,so it is necessary to design battery thermal management system,maintaining temperature is at 25℃～45℃.In this paper,Yutong E10 pure electric bus power battery pack as the research object,according to the design requirements of battery thermal management,research and optimize the cooling structure of the battery pack.This paper mainly focuses on the thermal management of the battery,and the battery will generate heat,so it can meet the requirements of cooling in summer and heating in winter.Considering the cost and cooling effect,this paper adopts the method of liquid-cooled cooling,designs and analyzes the cooling system of the battery pack of electric bus.This paper analyzes the physical model and working principle of lithium-ion battery and the heat generation and heat transfer principle of lithiumion battery;Besides,calculating the thermal parameters of lithium-ion battery and the rate of heat generation at different multiply,and laying the foundation for the subsequent simulation operation.Geometric modeling and thermal modeling of the battery for the electric bus and simulating the battery pack by ANSYS Fluent.And experiments to verify the simulation,the experimental values and simulation data for comparative analysis,to prove the correctness of the simulation.This paper mainly designs and optimizes the heat dissipation structure of the battery pack,so that the battery pack can meet the design requirements of the battery thermal management,and studies the influence of different cooling factors on the heat dissipation effect of the battery pack.To study the effect of different charging multiply,different ambient temperature and different rate of the charge influence the temperature of the battery pack.The study found that the higher the charging rate,the higher the battery temperature;The higher the ambient temperature,the higher the temperature of the battery.This paper studies the effect of single battery pack on the temperature of battery pack under different ambient temperature and different charging ratio.The results show that the higher the charging ratio,the higher the battery temperature;The higher the ambient temperature,the higher the battery temperature;The heat dissipation model of the battery pack was designed,and the temperature distribution of the battery pack under 1C,3C and 5C was simulated.According to the simulation results,the structure of the battery pack was optimized,and the single-in-and-single-out pipeline was changed into a double-in-anddouble-out pipeline.At the same time,a cold plate was placed on the side to simulate the temperature of the battery after the structure optimization.The temperature of the battery pack with optimized structure can meet the requirements of thermal design in working state.The influence of different cooling factors on the battery temperature was studied in the improved battery pack heat dissipation model.The results show that the increase of coolant flow rate has almost no effect on the battery temperature.The lower the coolant temperature,the lower the maximum battery temperature,but too low coolant temperature will make the battery pack temperature too low;The air convective heat transfer coefficient has little effect on the temperature of the battery pack.更多还原