Abstract:

Finite element models were created for stacked automotive supercapacitors using COMSOL Multiphysics 6.0, and thermal models were developed for two different thermal management methods, air- and liquid-cooled, to compare their effects on thermal management. First, the correlations between the maximum temperature of air- and liquid-cooled supercapacitors and the initial temperature of the heat exchange medium, inlet flow rate, and heat generation power of the supercapacitor modules were investigated within the same parameter variation range. The results show that the higher initial temperature of the heat transfer medium and greater heating power of the supercapacitor lead to higher maximum temperatures of the supercapacitor. Conversely, a faster average flow rate of the heat exchange medium at the inlet results in lower maximum temperatures of the supercapacitor. A critical flow rate of 1.5 m/s exists, beyond which the correlation between flow rate and maximum temperature weakens greatly. Second, based on the parametric study results, the heat transfer processes of these two thermal management methods were analyzed in-depth by setting the same operating parameters. This analysis explains opposite heat gradient direction in the height dimension between air- and liquid-cooled methods. The comparison of thermal management effects of the two methodsincludes factors such as maximum temperature, temperature difference, temperature distribution, and heat exchange time. The results show that liquid-cooled supercapacitors exhibit lower maximum temperatures, smaller temperature differences, more uniform temperature distribution, and much less heat exchange time compared to air-cooled supercapacitors and have better thermal management effects.

Key words: stacked supercapacitor, thermal management, thermal model, air cooling, liquid cooling, heat flow coupling