On Estimating Instantaneous Temperature of a Supercapacitor String Using an Observer Based on Experimentally Validated Lumped Thermal Model

The thermal model of energy storage elements such as batteries or supercapacitors (SCs) can be used as a platform to predict thermal behavior of the elements, which is essential from the point of view of monitoring and diagnostics. While the lumped thermal model for a single cylindrical SC cell and its extension to multicells string or module have been covered in technical literature, the multicells model has not been experimentally validated. This paper presents experimental validation of the existing lumped thermal model of multicylindrical cells based on an experimental setup of a forced cooled SC string consisting of eight 650 F cells. The determination of the parameters of such a thermal model is discussed and the validated model is used as a basis to design a closed-loop observer for estimating string temperature. Experimental results are presented to confirm its applicability for predicting instantaneous temperatures of each cell in the string.