车用动力电池包内部温湿耦合特性分析

汽车动力电池包内部的潮湿和凝露现象是温湿度耦合作用的结果，它直接影响电池性能、加剧电池失效且可能引发安全事故，但相关的研究工作还未得到足够关注，开展电池包内部温湿度耦合特性的分析工作尤为迫切。基于此，研究相应瞬态数值分析方法，求解电池包内部空间动态变化的温湿度分布情况。首先，分析电池包内部空间和外界环境的气体交换、热量传递过程，建立热湿传递的物理模型，并根据流体运动三大基本守恒定律以及温湿度耦合关系，建立对应的热湿传递数学模型；利用恒温恒湿箱和安装防水透气阀的电池包箱体进行热湿传递试验，验证外界环境动态变化的温湿度对电池包内部温湿度的影响以及电池包内部出现凝露和积水现象的条件；建立电池包及其内部空间的多物理场耦合三维模型，对电池包内外的热湿传递与温湿度耦合过程进行瞬态数值模拟，根据仿真计算结果与试验结果的对比验证模型的可靠性；采用真实气候环境数据定义模型中动态变化的电池包外部环境，从时间和空间分布的角度分析电池包内部温湿度的瞬态计算结果。研究结果表明：所提出的瞬态数值分析方法的可行性佳，得到了外界环境以及电池工作状态的动态变化对电池包内温湿分布、电池表面凝露时长的影响规律。

Analysis of Temperature-humidity Coupled Characteristics of Vehicle Power Battery Pack

The formation of moisture and condensation inside vehicle power battery packs is caused by the coupling effect of temperature and humidity. This formation directly affects the battery performance, aggravates battery failure, and may cause accidents. However, related research has not been conducted extensively. Hence, it is urgent to analyze the internal temperature and humidity coupling characteristics of battery packs. A transient numerical analysis method was developed in this study to evaluate the temperature and humidity distributions inside a battery pack. First, the gas exchange and heat transfer between the external and internal environments of the battery pack were analyzed to establish the physical model of the heat-humidity transfer. Based on the laws of conservation of mass, momentum, and energy and the coupling relationship between temperature and humidity, the corresponding mathematical model of heat and moisture transfer was established. Heat-humidity transfer experiments were performed using a constant temperature and humidity box and a battery pack with a waterproof air vent valve. The experimental data verified the coupled effect of the dynamic temperature and humidity of the external environment on the temperature and humidity inside the battery pack and the condensation and water accumulation conditions inside the battery pack. A multiphysics coupled 3D simulation model was established to perform transient numerical simulation of the heat and moisture transfer and coupled temperature-humidity process inside and outside the battery pack. The reliability of the model was verified through a comparison between the simulation and experimental results. Actual climatic data were used to define the dynamic environment outside the battery pack in the model. The transient calculation results for the temperature and humidity inside the battery pack were analyzed based on time and space distributions. The results verify the feasibility of the proposed method and show the effects of the dynamic changes in the external environment and the working state of the battery on the temperature and humidity distributions in the battery pack and the condensation duration on the battery surface.