The comparison of two supercapacitors lifetime estimated on the basis of accelerated degradation tests by means of stochastic models

The paper presents the results of the comparison of the lifetime estimation of two supercapacitors on the basis of the accelerated degradation tests by means of stochastic differential models. The acceleration of degradation processes was fulfilled by the increase of the operating voltage of the capacitors, while their reliability was assessed on the basis of the changes in equivalent series resistance. The reliability distribution function was determined using stochastic differential models. The model parameters were assessed based on the changes of supercapacitor parameter at the beginning of the testing process. In order to eliminate the effect of other factors accelerating the ageing process, supercapacitors were placed in a temperature chamber that provided a constant temperature during the tests. The paper describes the construction of the test setup, the tests procedure, and the method of reliability estimation. The use of two capacitors with different nominal voltages allowed for assessment of properties of particular parts of the test setup, as well as the proposed procedure for the tests and analysis of the results.