关键词: 绝热量热仪, 产热功率, 锂离子电池, 比热容, 垂向导热系数

Abstract:

Specific heat capacity and thermal conductivity are critical parameters for assessing the thermal safety of lithium-ion batteries. Although previous studies have examined the factors affecting these thermal properties, most have concentrated on the batteries' internal characteristics. Studies on the impact of external testing conditions on these parameters are scarce. This study introduces a method for testing the thermal properties of lithium-ion batteries using an adiabatic calorimeter. The approach facilitates the simultaneous determination of specific heat capacity and vertical thermal conductivity. The effects of varying the heating sheet size and the battery's temperature rise rate on test results were analyzed. Findings indicate that increasing the battery's temperature rise rate from 0.2 ℃/min to 0.8 ℃/min slightly reduces the average specific heat capacity by less than 1%, while significantly lowering the vertical thermal conductivity. Additionally, reducing the heating sheet size leads to a notable reduction in the average specific heat capacity, which affects the measured heat generation power. Although it has minimal impact on vertical thermal conductivity. Based on the experimental results, recommendations for optimizing testing conditions of lithium-ion battery thermal parameters are proposed. The maintenance of a constant heating sheet size and a moderate increase in the battery's temperature rise rate can improve testing efficiency without significantly compromising the accuracy of heat generation power measurements. To improve the reliability of thermal property testing, utilizing a larger heating sheet size and maintaining a controlled temperature rise rate is recommended, balancing accuracy and testing efficiency.

Key words: accelerating rate calorimeter, heat generation power, lithium-ion battery, specific heat capacity, vertical thermal conductivity