scholarly journals Determination of SoH of Lead-Acid Batteries by Electrochemical Impedance Spectroscopy

2018 ◽  
Vol 8 (6) ◽  
pp. 873 ◽  
Author(s):  
Monika Kwiecien ◽  
Julia Badeda ◽  
Moritz Huck ◽  
Kuebra Komut ◽  
Dilek Duman ◽  
...  
2018 ◽  
Vol 8 (8) ◽  
pp. 1308 ◽  
Author(s):  
Julia Badeda ◽  
Monika Kwiecien ◽  
Dominik Schulte ◽  
Dirk Sauer

Impedance or admittance measurements are a common indicator for the condition of lead-acid batteries in field applications such as uninterruptible power supply (UPS) systems. However, several commercially available measurement units use different techniques to measure and interpret the battery impedance. This paper describes common measurement methods and compares their indication for the state of health (SoH) to those of electrochemical impedance spectroscopy (EIS). For this analysis, two strings consisting each of 24 valve-regulated lead-acid (VRLA) batteries with a rated voltage of 12 V and about 7 Ah capacity were kept under standard UPS conditions in float charge for over 560 days. They were monitored continuously with a LEM Sentinel 2 and went into regular check-ups with impedance measurements by a Hioki BT3554 as well as electrochemical impedance spectroscopy (EIS) measurements with an impedance meter (μEIS). Today it is widely expected that solely the relative increase of the impedance reading is sufficient for the estimation of the available capacity. However, it can be shown that the measured relative increase deviates for different frequencies and therefore the choice of the excitation signal and measurement frequency does make a difference for the calculation of the available capacity. Finally, a method for a more decisive monitoring in field applications is suggested.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 775 ◽  
Author(s):  
Sebastián Feliu

From a technological point of view, measurement of the corrosion rate of magnesium (Mg) and its alloys is critical for lifetime predictions of Mg-based structures and for comparative assessments of their corrosion protection ability. Whilst weight loss, hydrogen evolution, and polarization curves methods are frequently used for measuring the corrosion rate, the determination of values by electrochemical impedance spectroscopy (EIS) is relatively scarce and has only been realized recently. This technique seems to be the most suitable for monitoring corrosion rate values due to its “non-destructive” character, its reproducibility, and its reliable determination of small corrosion rates, much lower than those measured by other techniques. This review aims to picture the state-of-the-art technique of using EIS for measuring the corrosion rate of Mg. This paper starts by introducing some fundamental aspects of the most widely used methods for monitoring the corrosion rate of Mg/Mg alloy and continues by briefly explaining some of the fundamental concepts surrounding EIS, which are essential for the user to be able to understand how to interpret the EIS spectra. Lastly, these concepts are applied, and different approaches that have been proposed to obtain quantitative values of corrosion rate since the 1990s are discussed.


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