Ni/MH电池过充电过程热效应分析

Thermal behavior analysis of nickel/metal hydride battery during overcharging

论文采用二维热模型分析了圆柱型Ni/MH电池在过充电过程中的热效应.实验提供了更为精准的数据以建立精确的热模型.利用石英频率微量热仪对电池的热容量以及电池在不同电流过充电时的发热量和散热速率进行了测量,继而将散热速率曲线拟合成线性函数和三段不同的指数函数.线性阶段之后的散热过程符合数学微分表达式,这些表达式有助于理解过渡阶段和过充电阶段散热速率的变化规律.热传导方程中产热速率采用理论计算值.最后使用FEM模拟了电池在1C,3C,5C充电过程每一阶段末时刻的电池内部温度场分布,结果相对准确.

To analyze the thermal behavior of the cylinder Ni/MH battery during overcharging,a two-dimensional thermal model is provided in this work.More reliable data is provided to create the precise thermal model.The amount of heat of the battery during overcharging at different currents was measured using quartz frequency microcalorimeter. To obtain the heat transfer coefficient of the battery during overcharging,the heat dissipation rate was fitted into linear functions and three different exponential functions from the temperature value measured by the microcalorimeter.The heat dissipation process after the linear stage was regared to accord with some mathematical differential expressions,which facilities understanding of the variation rule of heat dissipation rate during the transition stage and overcharging process.Theoretical values were used as heat generation rates in the heat transport equation.Using the measured data,the internal temperature profiles at the end of each stage during charging at 1C,3C and 5C were simulated using FEM.