Study On The Multi-physical Field Dynamic Behaviors Of Supercapacitors

Supercapacitor is one kind of new energy device, which has a broad application prospect. Its working mechanism is different from batteries and traditional electrostatic capacitors. Its main advantage is, that it has a high capacitance, high power density, rapid charging and discharging, no pollution, long cycle life and low temperature performance.An ideal supercapacitor needs good electrical properties, including large specific capacitance, wide working voltage range and small ohm impedance, which are affected by its electrochemical behaviors and thermal behaviors. The behaviors, which both influence each other and restrict each other, are mainly decided by the materials, structure and running environment.In this paper, in view of spiral wound supercapacitors’structure and running environment, an electrochemical model and a thermal model were built and coupled by the finite element analysis software COMSOL Multiphysics, for in-depth analysis of the multi-physical field dynamic behaviors.Firstly, an electrochemical model was built on the basis of electrochemical theory, which was analyzed by COMSOL with the finite element method. Its time-space electrochemical behaviors were simulated under different constant current charge and discharge, to obtain its electric performance parameters. The method can be used to simulate the supercapacitors’internal micro dynamics and external performance, which provides a new method for the device’s virtual dynamic research.Secondly, a thermal model was established on the basis of thermodynamic theory, and then the coupling of thermology and electrochemistry was realized by COMSOL. The supercapacitor’s time-space temperature field was simulated to analyze the influence of current density and heat convection coefficient.Finally, based on the above theories and methods of multi-physical fields, the influence of the package units structure on electrochemical and thermal behaviors was studied. According to the different application environment, the corresponding optimization suggestions were put forward, which realized the virtual optimization design for the supercapacitor.