内嵌树形翅片相变层电池热管理性能

Thermal management performance of batteries with embedded tree-like fins for phase transition layers

针对被动式电池冷却方法存在相变材料导热性能差,无法及时释放电池热量的问题,本工作提出内嵌树形翅片强化相变层的传热特性。采用焓-孔隙率法建立了描述树形翅片-相变材料动态熔化传热过程的数学模型,数值分析了具有不同结构翅片相变材料的围护层,在1 C、2 C和3 C放电倍率下对电池温度的影响。与石蜡作为围护层相比,在3 C放电倍率下,石蜡内嵌直翅片可降低电池温度9.7 K;内嵌树形翅片时,相比于内嵌直翅片相变材料围护层电池温度可降低1.4 K。当树杈与树干的长度比为1.2时,内嵌树形翅片相变围护结构应用于电池热管理系统,可以得到较好的传热特性。

Due to the low thermal conductivity of the phase change materials(PCM)in the cooling battery,the copper tree fins embedded in the envelope structure of the PCM are proposed to release heat in time.A mathematical model was established to describe the dynamic melting and heat transfer process of the tree-finned PCM using the enthalpy-porosity method.The influence of the envelope with the tree-finned PCM of different structures on the cell temperature was numerically analyzed at discharge rates of 1 C,2 C,and 3 C.Compared with using paraffins as the envelopes,the cell temperature can be reduced by 1.4 K with straight fins.When embedded with tree fins,however,the cell temperature can be reduced by 1.4 K compared to that with straight fins.When the ratio of the branch length to trunk length is 1.2,the PCM envelope embedded with tree fins can obtain better heat transfer characteristics for battery thermal management systems.