A pulsed discharge regime (GITT) was used to investigate the ohmic internal resistance of Na/NiCl2 cells, also known as ZEBRA Cells. Two methods were chosen to determine the internal resistance. On the one side the voltage response of the corresponding current enables a calculation. On the other side the potentiostatic electrochemical impedance spectroscopy was used to measure cell spectra including the ohmic internal resistance. The cells were investigated within five different operating temperatures (300°C – 180°C with 30 K steps). Results show that the ohmic internal resistance of a Na/NiCl2 is increasing when the operating temperature is decreasing, mainly due to the decrease of ionic conductivity of β^'' separator and the secondary electrolyte NaAlCl4. As a direct consequence, there is a significant capacity loss. Therefore, the operating temperature can be identified as capacity limiting factor.
Battery models are mathematical systems that aim to simulate real battery cell sufficiently accurately. Finding a comprise between complexity, computational effort and accuracy is thereby key. In particular, modelling sodium–nickel–chloride/iron-chloride cells (Na-NiCl2/FeCl2), as a promising alternative for stationary energy storage, bears some challenges. The literature shows a few interesting approaches, but in most of them the second active material (NiCl2 or FeCl2) or the entire discharging/charging cycle is not considered. In this work, an electrochemical and thermal model of Na-NiCl2/FeCl2 battery cells is presented. Based on an equivalent circuit approach combined with electrochemical calculations, the hybrid model provides information on the performance of the cell for charging and discharging with a constant current. By dividing the cathode space into segments, internal material and charge flows are predicted, allowing important insights into the internal cell processes. Besides a low calculation effort, the model also allows a flexible adaption of cathode composition and cell design, which makes it a promising tool for the development of single battery cells as well as battery modules and battery systems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.