【作者】 项毅；

【导师】 唐志国； 张宝鑫；

【作者基本信息】 合肥工业大学 ， 动力工程（专业学位）， 2025， 硕士

【摘要】 作为电动汽车的供能元件,动力电池会直接影响其安全性能和续航能力。随着电动汽车动力电池正朝着高充放电倍率方向发展,其产热量也随之大幅度增加,导致其温度显著上升,引发安全隐患。为了解决动力电池的散热难题,满足高温度均匀性需求,确保其安全高效运行,开发可靠的电池热管理系统是至关重要的。为了解决传统通道液冷板温度均匀性差、压降高等缺点,本文将分形通道液冷板应用于电池热管理系统中,提出了不同的分形通道排布方式,以电池中间截面的温度标准差(T_std)和液冷板的综合评价指标（PEC）作为评价指标,在4C放电倍率下研究了单层分形通道结构参数对液冷板和电池性能的影响,结果表明T_std和PEC随着结构的变化呈现相同的变化趋势,也就是说越高的PEC往往要以越差的电池温度均匀性为代价。为了得到一组最佳的液冷板结构参数以获取较小的T_std和较大的PEC,本文采用了两种优化方法,即人工神经网络与遗传算法（ANN-GA）结合和响应面法与遗传算法（RSM-GA）结合,对液冷板结构参数进行多目标优化,结果显示,与单因素分析的初始结构相比,两种优化后结构的PEC分别增加了3.93%和0.72%,T_std分别下降了7.79%和25.45%。可以看出通过ANN-GA得到的最优结构对液冷板性能的提升更大,而通过RSM-GA得到的最优结构对电池的温度均匀性的提升更大。随后针对ANN-GA得到的最优结构,研究了冷却液入口流速和电池放电倍率对其性能的影响。结果显示,增大冷却液入口流速最多可以将电池的最高温度(_max)和最大温差(Δ_max)降低至31.43℃和4.57℃,但液冷板的进出口压降（ΔP）也会随之不断增大;增大电池放电倍率则会使电池的最高温度和最大温差显著上升。为了进一步强化液冷板的换热性能,提高电池的温度均匀性,基于ANN-GA的优化结构,提出了一种双层分形通道液冷板,通过数值计算研究了液冷板进出口位置、上下层分形通道排布方法和冷却液入口流速对其性能的影响。结果表明,当冷却液入口流速为1.25m/s、放电倍率为4C时,进出口位于异侧且上下层通道均采用沿流动方向的分形通道由合到分结构的双层通道液冷板可以将电池的最高温度控制在31.22℃,最大温差控制在4.15℃。为了直观的表示液冷板的耗能,引入系统的泵功率P,将该双层通道液冷板与单层分形通道液冷板对比后发现,通过改变冷却液入口流速,该双层分形通道液冷板可以在更少的功耗下实现更好的电池温度均匀性。在此流速下（1m/s）,与单层通道BTMS（入口流速为1.5 m/s）相比,该双层分形通道液冷板的电池最大温差和泵功降低了5.47%和7.69%。更多还原

【Abstract】 As the energy supply component of electric vehicles,power batteries directly affect their safety performance and endurance.With the development of electric vehicle power batteries towards high charging and discharging rates,it will cause a significant increase in the heat generation of power batteries,leading to a significant rise in their temperature and posing safety hazards.In order to solve the heat dissipation problem of power batteries,meet the high temperature uniformity requirements,and ensure their safe and efficient operation,it is crucial to develop a reliable battery thermal management system.In order to address the shortcomings of poor temperature uniformity and high pressure drop in traditional channel liquid cooled plates,the fractal channel liquid cooled plates is applied to battery thermal management systems in this article,and different fractal channel arrangements are proposed.The temperature standard deviation(T_std)of the middle section of the battery and the comprehensive evaluation index（PEC）of the liquid cooled plate are used as evaluation indicators to study the influence of fractal channel structural parameters on the performance of the liquid cooled plate and battery at 4C discharge rate.The results show that T_std and PEC exhibit the same trend of change with structural changes,which means that higher PEC often comes at the cost of poorer battery temperature uniformity.In order to obtain the optimal a set of structural parameters for the liquid cooled plate to achieve smaller T_std and larger PEC,two optimization methods are adopted in this article,namely the combination of artificial neural network and genetic algorithm（ANN-GA）and the combination of response surface method and genetic algorithm（RSM-GA）,to carry out multi-objective optimization of the structural parameters of the liquid cooled plate.The results show that compared with the initial structure of single factor analysis,the PEC of the two optimized structures increased by 3.93%and 0.72%respectively,and T_std decreased by 7.79%and 25.45%respectively.It can be seen that the optimal structure obtained through ANN-GA has a greater improvement in the performance of the liquid cooled plate,while the optimal structure obtained through RSM-GA has a greater improvement in the temperature uniformity of the battery.Subsequently,based on the optimal structure obtained from ANN-GA,the effects of coolant inlet flow velocity and battery discharge rate on its performance were studied.The results showed that increasing the coolant inlet flow velocity can reduce the maximum temperature(_max)and maximum temperature difference(Δ_max)of the battery to 31.43℃and 4.57℃,respectively.However,the pressure drop between the inlet and outlet of the liquid cooled plate（ΔP）will also increase accordingly.Increasing the battery discharge rate will significantly increase the maximum temperature and temperature difference of the battery.In order to further enhance the heat transfer performance of the liquid cooled plate and improve the temperature uniformity of the battery,a double-layer fractal channel liquid cooled plate is proposed based on the optimized structure of ANN-GA.The influence of the inlet and outlet positions of the liquid cooled plate,the arrangement method of the fractal channels in the upper and lower layers,and the inlet flow velocity of the coolant on its performance are studied through numerical calculations.The results showed that when the coolant inlet flow velocity is 1.25m/s and the discharge rate is 4C,the inlet and outlet are located on opposite sides,and both the upper and lower channels adopt a fractal channel structure,which is from merging to splitting along the flow direction,can control the maximum temperature of the battery at 31.22℃and the maximum temperature difference at 4.15℃.In order to intuitively represent the energy consumption of the liquid cooled plate,the pump power of the system P is introduced.After comparing the double-layer channel liquid cooled plate with the single-layer fractal channel liquid cooling plate,it is found that by changing the inlet flow velocity of the coolant,the double-layer channel liquid cooled plate can achieve better battery temperature uniformity with less power consumption.At this flow velocity（1m/s）,compared with single-layer channel BTMS（the inlet velocity is 1.5m/s）,the battery maximum temperature difference and of the double-layer channel liquid cooled plate is reduced by 5.47%and 7.69%,respectively.更多还原