Influence of relaxation process on supercapacitor time response

This paper deals with the fractional order modelling of the supercapacitor voltage response for a given current profile. The model is obtained using the porous electrode theory applied on the supercapacitor case. In order to simplify the complexity of the model, it is assumed that there is no diffusion process in the electrolyte. These assumption leads to neglect the supercapacitor self-discharge. So, we intend to combine both frequency and time identification methods. The differences on the obtained results show the importance of the experimental protocol. A numeric approach leads to estimate the supercapacitor initial state influence on the voltage response of a same model. An experiment is done on a 2000F/2.7V element to validate the assumption done and the result allows estimating the current sign dependency of the capacitance.

[1]  Thomas Christen,et al.  Theory of Ragone plots , 2000 .

[2]  R.W. De Doncker,et al.  Modeling the dynamic behavior of supercapacitors using impedance spectroscopy , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[3]  O. Briat,et al.  Ultracapacitors self discharge modelling using a physical description of porous electrode impedance , 2008, 2008 IEEE Vehicle Power and Propulsion Conference.

[4]  B. Conway.  Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications , 1999 .

[5]  A. Hollenkamp,et al.  Carbon properties and their role in supercapacitors , 2006 .

[6]  J. H. van Lenthe,et al.  The metal side of the electrical double layer at the metal/electrolyte interface An ab initio quantum chemical cluster study , 1984 .

[7]  R. Bonert,et al.  Characterization of double-layer capacitors (DLCs) for power electronics applications , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).