基于复合相变材料的电池组散热性能分析

Analysis of heat dissipation performance of battery pack based on composite phase change material

首先对某21700三元锂离子电池进行了内阻和物性实验,之后建立单体锂离子电池自然对流散热模型并进行验证,最后基于膨胀石墨/石蜡复合定型相变材料设计了电池组散热结构。通过数值模拟方法,分析了相变材料散热的有效性,阐述了相变材料的热物性和环境温度对散热性能的影响。石墨的含量应适中,相变材料的热导率达到一定程度后,相变焓值和比热对散热性能的影响更大。环境温度升高则相变材料的潜热消耗越快,无法达到电池组的散热要求。

The internal resistance and physical properties of a 21700 ternary lithium-ion battery were tested firstly.Then the natural convection heat dissipation model of the single lithium-ion battery was established and verified.Finally,the heat dissipation structure of the battery was designed based on the expanded graphite/paraffin composite phase change material.Through the numerical simulation method,the effectiveness of heat dissipation of phase change material(PCM)was analyzed,and the influence of thermal properties of PCM and ambient temperature on heat dissipation performance were expounded.The content of graphite should be moderate,after the thermal conductivity of the PCM reaches a certain level;the phase change enthalpy and the specific heat have a greater influence on the heat dissipation performance.When the ambient temperature rises,the latent heat consumption of the PCM is faster,and the heat dissipation requirement of the battery pack cannot be achieved.