Novel experimental investigation of supercapacitor ageing during combined life-endurance and power-cycling tests

Paolone

2016

Self Cite

The paper proposes a study of the phenomenology driving the ageing mechanisms of electrochemical double layer supercapacitors (SCs) during their most common operating conditions. In particular, the paper focuses on the so-called life endurance (LE) and power cycling (PC) stresses. The paper first provides a description of the variables governing the SC behaviour at the microscopic scale (i.e., porosity of the electrode surface, diffusion and conductivity of the electrolyte). Then, the paper discusses the link between these variables and the ones describing the SC behaviour at the macroscopic scale (i.e., temperature of the electrolyte and delivered current). This analysis is applied to both LE and PC stresses and as well as to their combination. The discussions make reference to experimental results obtained at the Author's laboratory by means of a dedicated test bench.

Section: Torregrossa M Paolone / Journal Of Energy Storage Xxx (mentioning

confidence: 99%

“…[19,20]. In what follows, a brief description of the experimental test bench, adopted devices and testing conditions are given.…”

Section: Experimental Test Benchmentioning

confidence: 99%

Section: Power Cycling Ageing Stressmentioning

confidence: 99%

“…the ESR, it has been experimentally investigated that it does not change considerably during a PC test at nominal temperature [19]. (see Fig.…”

Section: Torregrossa M Paolone / Journal Of Energy Storage Xxx (mentioning

confidence: 99%

See 2 more Smart Citations

Modelling of current and temperature effects on supercapacitors ageing. Part I: Review of driving phenomenology

Paolone

2016

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“…5 In order to mitigate/eliminate this bias, we Table 2 we can see that the inferred value of the C PC1 is of 302.6 F. Also this value can be considered reasonable since is lower than the corresponding one after a LE test (it has been already underlined that during a PC stress test the ageing phenomena are amplified compared to those during a LE stress test). 5 Further details concerning this aspect can be found in [16].…”

Section: General Overviewmentioning

confidence: 99%

Modelling of current and temperature effects on supercapacitors ageing. Part II: State-of-Health assessment

Paolone

2016

Self Cite

This second part of the paper proposes a model for predicting the State-of-Health (SOH) of electrochemical double layers supercapacitors (SCs) during combined high-pulsed power cycling and high-temperature life endurance stresses. The evolutions of the SC capacitance, C SC , during these specific types of stresses have been discussed in part I and, based on the phenomenological observations we made, we here predict the C SC evolution by means of a dedicated model. The inputs of the proposed model are the SC delivered charge and the duration of the temperature stress above the rated one; the output is the C SC . The main virtue of the model is its capability to take into account the presence of the C SC recovering and accelerated ageing that cannot be represented by other models available in the literature. The validation of the proposed SC ageing model is carried out by means of experimental results, other than those used to infer the model, obtained on a 365 F SC stressed by combined life-endurance and power-cycling stresses over a time window of 35 days.

Macroscopic indicators of fault diagnosis and ageing in electrochemical double layer capacitors

Toghill

Amstutz

et al. 2015

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The ageing behaviour of electric double layer (EDLC) supercapacitors during over-temperature and overvoltage stresses is described. Specific experimental tests were carried out in order to reproduce, under laboratory controlled conditions, the above-mentioned stresses. The obtained results are discussed and interpreted to define indicators that distinguish between over-temperature and over-voltage faults occurring in these devices. For each stress type post-mortem examinations of the EDLCs were performed to observe any specific physical damage. These examinations have been used to define the fundamental assumptions of the proposed fault indicators. Three fault indicators were identified and related to the evolution of the following SC parameters: (i) the equivalent series resistance, (ii) capacitance and (iii) decay voltage during the relaxation phase. Additionally, new accelerated ageing and recovering phases were detected during combined high-pulsed power cycling and life endurance stresses.