Four stages of thermal effect coupled with ion-charge transports during the charging process of porous electrodes

Due to the complexity of thermal effects in porous electrodes, the process of temperature rise in supercapacitors is difficult to be quantified by some simple but physically meaningful formulas. Here, the stack-electrode model is applied to investigate this issue both analytically and numerically. The numerical results show the process has three relaxation times, which divide that into four stages controlled by heat generation (HG) or heat transfer (HT). Temperature rise is first controlled by HG in the bulk phase, then by HG in both porous electrodes and bulk phase, then mainly by HT, and finally all by HT. The analytical formulas of three relaxation times and temperature rise under different structural parameters and intensity of heat dissipation are obtained. These formulas are expected to indicate the contribution of the different stages to total temperature rise, thus to guide the design of cooling methods of supercapacitors during the different stages.

Automated summary

This study applies the stack-electrode model to investigate the thermal effects in porous electrodes. The results show that the temperature rise process has three relaxation times and four stages controlled by heat generation or heat transfer. Analytical formulas for the relaxation times and temperature rise under different structural parameters and heat dissipation intensity are obtained. These formulas can guide the design of cooling methods for supercapacitors during different stages.