| Supercapacitor is one kind of the new energy storage devices with fast charge and discharge,high power,long working life and environmentally friendly operation,which make itself a potential power source for electric vehicles.However,variations of performance parameters for a supercapacitor need to be further researched,including the equivalent serial resistance(ESR),capacitance,and the temperature variation during charging and discharging cycles.And the design of cooling system for the supercapacitor module compartment of an electric bus also needs moer exploration.This paper focused on the variations of ESR and capacitance of electric double layer supercapacitor with temperature and current.Temperature variation of a supercapacitor during galvanostatic cycling was also analyzed,and the reversible heat was responsible for the temperature oscillation.With the number simulations and experiments,the variation and impacting parameters of reversible heat were discussed.And the temperature distribution inside supercapacitor was analyzed by thermal model established by reversible heat and varied ESR and experimental data.Lastly,the cooling system of supercapacitor module compartment for an electric bus was analyzed,and the optimized system was verified on the road.1.Experimental studies were performed on a supercapacitor by galvanostatic discharge and continuous charging and discharging.The variations of ESR and capacitance with temperature and current were summarized.And the temperature variation properties of supercapacitor sample during charge and discharge cycling were analyzed under different ambient temperature and current.2.A method to evaluate the reversible heat has been deduced from the surface Gibbs free energy at the interface between electrode and electrolyte through the energy conservation.And the effects of temperature,current and electrolyte concentration on the reversible heat were discussed combining with calculations and experiments.3.Thermal behaviors of supercapacitor during charging and discharging were simulated with reversible heat and Joule heat caused by the varied ESR.And the temperature distributions inside supercapacitor were studied with simulated and experimental data too.4.The cooling system of supercapacitor module compartment did not work well because of the effect of external air on the airflow distribution inside compartment when electric bus ran on the road.Under the worse case,the cooling air may even not be accessible to the compartment.In this paper,the cooling system of compartment was studied,and the airflow distribution inside compartment was optimized.Through the simulations and experiments,the optimization was proved to be effective. |
