基于对联热电偶的液冷板进出口小温差测量

Measurement of small temperature difference between import and export of liquid cooling plate based on coupled thermocouple

锂离子动力电池液冷板进出口温差较小因而难以精确测量,严重影响了对于动力电池热状态的准确分析。针对该问题进行了试验研究,提出了基于对联热电偶的小温差测量方法,直接测量温差热电势,尽可能地减少温度变送误差与传感器正负偏差;采用双恒温油槽完成对所提方法的标定及误差分析,获得了适用于基础温度293~393 K、温差20 K以内的温差测量经验公式。将该公式应用于某型号液冷板的热平衡性能试验,结果表明,与传统温差测量方法相比,可以将热平衡误差由9.4%减小到3.1%。

It is so small to measure accurately for the temperature difference between the import and export of the liquid cooling plate of lithium-ion power battery,which seriously affects the accurate analysis of the thermal state of the power battery.In this paper,a small temperature difference measurement method based on compound thermal couple was proposed.A coupled thermocouple was formed by welding the temperature compensation ends of two identical thermocouples together.This method can directly measure the thermoelectric potential of temperature difference,so as to minimize the positive and negative deviation between the temperature transducer error and the sensor.The calibration and error analysis of the method were conducted by using double constant temperature oil tank.Empirical formulas for temperature difference measurement were obtained,which were suitable for the base temperature of 293-393 K with the temperature difference of less than 20 K.This method was applied to practical thermal balance experiment of cooling plate and the result showed that this method could reduce the error of thermal balance from 9.4%to 3.1%.