Temperature distribution of supercapacitors prepared by various technologies

Supercapacitors, also known by different names such as electrostatic double-layer capacitors (EDLCs) or ultra-capacitors, are electrical storage devices still in development. These devices require fast and reliable methods of assessing their state-of-health. Thermographic imaging is a method which can be applied with this aim due to its popularity, and the high negative impact of overheating on a supercapacitor’s parameters. Moreover, thermographic imaging can be easily used to identify any hot spots, present during charging and discharging while in use. These devices are comprised of porous carbon electrodes and an electrolyte, and during the charging/discharging process, extensive heat may be generated and dissipated there. We have observed temperature fluctuations and were able to identify the inhomogeneity of the tested structures. The electrical parameters (capacitance C and equivalent serial resistance ESR) were measured to determine deterioration of the specimen as requested by the industrial standard. X-ray examination of the samples was performed to identify the shape of the applied metal charge collectors. Both techniques indicated areas where eventual overheating took place due to their electrodes’ shape, suggesting their further optimisation. The proposed method is much less accurate than the calorimetric methods, determining energy flows, but is still sufficient to identify problems with heat dissipation in the developed specimens. Finally, some conclusions about the ability to apply this method in practice to monitor supercapacitors during use were presented.