| Supercapacitors have the advantages of high power density,low internal resistance and long cycle life,etc.They are widely used in new energy electric vehicles.This paper makes a study on the temperature characteristics,thermal behavior characteristics and thermal management system of supercapacitors.The one-dimensional electrochemical model and three-dimensional heat transfer model simulation methods are used for experimental tests and as a comparison to study the thermoelectric coupling characteristics of supercapacitors and their performance variation patterns.By establishing the 1D electrochemical model and 3D heat transfer model of supercapacitor in COMSOL and combining with the change of air flow field,the simulation optimization design of air-cooled thermal management system and phase change material composite heat sink system of supercapacitor is made.The effects of operating parameters such as ambient temperature,positive and negative pole thickness,positive and negative pole thickness ratio on the heat generation,temperature distribution and working performance of supercapacitor during charging and discharging as well as the effects of key parameters in thermal management system on the heat dissipation results are analyzed to improve the heat dissipation efficiency of thermal management system and obtain a good temperature uniformity performance,which has some practical significance for the research of thermal management system of supercapacitor.The main research work and conclusions of this paper are as follows.(1)The results show that the ESR of the supercapacitor increases with decreasing temperature,the capacitance value decreases with decreasing temperature,and the change in characteristic parameters of the hybrid supercapacitor is more sensitive to temperature than its double-layer supercapacitor.(2)An electrochemical model as well as a heat transfer model were established to analyze the electrochemical and thermal behavior characteristics of the supercapacitor,and the effects of different negative electrode thicknesses on the performance parameters as well as the thermal behavior characteristics of the hybrid supercapacitor were investigated.The results show that the increase of negative electrode thickness makes the energy density of the hybrid supercapacitor,but also causes the decrease of its heat dissipation capability and power density;the ambient temperature and the circulating current magnitude are the most important factors affecting the temperature variation of the supercapacitor.(3)The air-cooled heat dissipation design of the supercapacitor module was carried out,and the effects of the supercapacitor pitch,air speed,inlet temperature,and ventilation method on the heat dissipation results were analyzed in detail by using the control variable method.The study shows that serial ventilation has a simple structure and good heat dissipation effect,but the temperature uniformity is slightly worse than parallel ventilation;air speed and inlet temperature have the greatest influence on the heat dissipation effect,and increasing the air speed and reducing the inlet temperature can significantly improve the heat dissipation effect,among which the air speed has a greater influence on the temperature uniformity,and the inlet temperature has a more obvious influence on the maximum temperature of the supercapacitor unit.(4)In response to the poor heat dissipation effect of air-cooled heat dissipation in high temperature environment,a composite heat dissipation system was designed by combining phase change material and heat pipe to meet the heat dissipation needs of supercapacitor in high temperature environment.The research results show that the composite phase change material alone cannot meet the heat dissipation needs,and after the composite heat dissipation system is formed with heat pipe and fin,the maximum temperature of the supercapacitor single body is 317.58 K and the maximum temperature difference is 3.8 K to meet the heat dissipation needs. |
