Electro-thermal modelling of a supercapacitor and experimental validation

• A physical-based electro-thermal modelling of a supercapacitor is accomplished.
• The electrical and thermal models are represented alike as equivalent circuits.
• A fitting process for the parameters of both models is developed.
• Validation of the models is performed in various situations proving their accuracy.
• The models are valid for the entire temperature and frequency operating range.

This paper reports on the electro-thermal modelling of a Maxwell supercapacitor (SC), model BMOD0083 with a rated capacitance of 83 F and rated voltage of 48 V. One electrical equivalent circuit was used to model the electrical behaviour whilst another served to simulate the thermal behaviour. The models were designed to predict the SC operating voltage and temperature, by taking the electric current and ambient temperature as input variables. A five-stage iterative method, applied to three experiments, served to obtain the parameter values for each model. The models were implemented in MATLAB-Simulink®, where they interacted to reciprocally provide information. These models were then validated through a number of tests, subjecting the SC to different current and frequency profiles. These tests included the validation of a bank of supercapacitors integrated into an electric microgrid, in a real operating environment. Satisfactory results were obtained from the electric and thermal models, with RMSE values of less than 0.65 V in all validations.