Abstract

This study investigates the electrical and thermal characteristics of a cylindrical lithium-ion cell with an axisymmetric two-dimensional lumped model. The cell is completely discharged at 0.5, 1 and 1.5 C rates under 0, 20 and 50 °C operating temperatures. Both the open circuit voltage values and the average specific heat value of the cell are measured and used as an input to the model. The model uses the variable internal resistance approach to evaluate the voltage variation of the cell that is obtained from experimental data. A cylindrical lithium-ion cell has a spiral construction that involves multiple layers. However, these layers are assumed as a uniform material in the lumped model. The lumped model in COMSOL Multiphysics couples the heat transfer and lumped battery interfaces so it allows predicting the surface temperature of the cell during discharging processes. The experimental results point out that the operating temperature inversely affects the internal resistance and the heat generation within the cell during a discharging process. Furthermore, it is found that the capacity of the cell significantly decreases at low operating temperatures. Finally, the predicted temperature profile follows the same trend with the experimental data and is consistent at each operating condition.

摘要

这项研究调查了具有轴对称二维集总模型的圆柱形锂离子电池的电学和热学特性。在0、20和50°C的工作温度下，电池以0.5、1和1.5 C的速率完全放电。测量电池的开路电压值和平均比热值，并将其用作模型的输入。该模型使用可变内部电阻方法来评估从实验数据获得的电池电压变化。圆柱形锂离子电池具有螺旋结构，涉及多层。但是，在集总模型中假定这些层是均匀的材料。COMSOL Multiphysics中的集总模型将传热和集总电池接口耦合在一起，因此可以预测放电过程中电池的表面温度。实验结果指出，在放电过程中，工作温度会反过来影响电池内部的电阻和热量的产生。此外，发现在低工作温度下电池的容量显着降低。最后，预测的温度曲线与实验数据遵循相同的趋势，并且在每种操作条件下均保持一致。发现在低工作温度下电池的容量显着降低。最后，预测的温度曲线与实验数据遵循相同的趋势，并且在每种操作条件下均保持一致。发现在低工作温度下电池的容量显着降低。最后，预测的温度曲线与实验数据遵循相同的趋势，并且在每种操作条件下均保持一致。