C/LiFePO_4动力蓄电池的热行为

Thermal behavior of C/LiFePO_4 power secondary battery

为了明确圆柱形C/LiFePO4动力蓄电池放电过程中的温度特性及其产热机理,利用自动充放电仪对其在不同倍率放电过程中表面温度的变化进行研究,并对该电池在放电过程中的产热率进行计算。结果表明:相同放电时间的表面温度增加与放电电流呈抛物线关系,放电结束时表面温度增加则与放电电流呈线性关系;电池内部的热效应主要为不可逆阻抗热和电池反应的可逆热效应,0.3C、1C、2C和3C放电时,不可逆阻抗热的平均产热率分别是总平均产热率的85.0%、98.0%、99.4%和99.6%,电池反应的可逆热效应所占比例很小;小电流放电时,电池表面温度的下降与电池反应的可逆热效应有关。

In order to investigate the temperature characterize and heat generation mechanism of a cylindrical power secondary battery using graphite and LiFePO4 as anode and cathode,its surface temperature change at different discharge rates were studied by a automatic charge and discharge device.Moreover,its heat generation rate during discharge was calculated.The results show that,at the same discharge time,the relationship between the surface temperature rising and the discharge current is parabolic,whereas at the end of discharge,the surface temperature rising is a liner relationship with the discharge current.The irreversible resistive heating and reversible entropic heat are the major heat generation sources inside the battery.The average rates of the irreversible resistive heating at 0.3C,1C,2C and 3C rate are about 85.0%,98.0%,99.4% and 99.6% of that of the total heat generation,respectively.The proportion of reversible entropic heat is very small.At low discharge current,the surface temperature drop is dominated by reversible entropic heat.