A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements

Graphite felts are the most commonly used electrode materials in vanadium redox flow batteries. In the conventional cell design, flat sheets of graphite bipolar plates and porous graphite felts are stacked without any bonding, which requires a certain degree of compression to minimize the contact re...

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Main Authors: Ghimire, Purna C., Bhattarai, Arjun, Schweiss, Rüdiger, Scherer, Günther G., Wai, Nyunt, Yan, Qingyu
Other Authors: School of Materials Science and Engineering
Format: Journal Article
Language:English
Published: 2020
Subjects:
Online Access:https://hdl.handle.net/10356/143309
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author Ghimire, Purna C.
Bhattarai, Arjun
Schweiss, Rüdiger
Scherer, Günther G.
Wai, Nyunt
Yan, Qingyu
author2 School of Materials Science and Engineering
author_facet School of Materials Science and Engineering
Ghimire, Purna C.
Bhattarai, Arjun
Schweiss, Rüdiger
Scherer, Günther G.
Wai, Nyunt
Yan, Qingyu
author_sort Ghimire, Purna C.
collection NTU
description Graphite felts are the most commonly used electrode materials in vanadium redox flow batteries. In the conventional cell design, flat sheets of graphite bipolar plates and porous graphite felts are stacked without any bonding, which requires a certain degree of compression to minimize the contact resistance. Excessive compression of the electrode, however, leads to non-uniform flow distribution and potential occurrence of zones with the retarded flow of electrolyte. This study investigates a wide range of electrode compressions and their effect on the cell performance. The results show that a compression of 25% is the optimal trade-off between contact resistance, homogeneity of flow distribution and pumping losses. Moreover, spatially resolved measurements using a segmented cell are employed to visualize the flow distribution across the electrode in real time. The open circuit voltage after the termination of the cell charge/discharge is converted to the corresponding state of charge (SOC) of the electrolyte, and the difference between the theoretical and experimental state of charge of electrolyte is used to quantify the flow distribution across the electrode. The results show that the optimum conversion of the reactant can be achieved during a single pass at 25% electrode compression. This method of segmentation is simple and scalable to any size of the battery.
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spelling ntu-10356/1433092023-07-14T15:59:21Z A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements Ghimire, Purna C. Bhattarai, Arjun Schweiss, Rüdiger Scherer, Günther G. Wai, Nyunt Yan, Qingyu School of Materials Science and Engineering Energy Research Institute @ NTU (ERI@N) Engineering::Materials Vanadium Redox Flow Battery Electrode Compression Graphite felts are the most commonly used electrode materials in vanadium redox flow batteries. In the conventional cell design, flat sheets of graphite bipolar plates and porous graphite felts are stacked without any bonding, which requires a certain degree of compression to minimize the contact resistance. Excessive compression of the electrode, however, leads to non-uniform flow distribution and potential occurrence of zones with the retarded flow of electrolyte. This study investigates a wide range of electrode compressions and their effect on the cell performance. The results show that a compression of 25% is the optimal trade-off between contact resistance, homogeneity of flow distribution and pumping losses. Moreover, spatially resolved measurements using a segmented cell are employed to visualize the flow distribution across the electrode in real time. The open circuit voltage after the termination of the cell charge/discharge is converted to the corresponding state of charge (SOC) of the electrolyte, and the difference between the theoretical and experimental state of charge of electrolyte is used to quantify the flow distribution across the electrode. The results show that the optimum conversion of the reactant can be achieved during a single pass at 25% electrode compression. This method of segmentation is simple and scalable to any size of the battery. Accepted version This research was financially and technically supported by Nanyang Technological University, Singapore, and SGL Carbon GmbH, Germany. 2020-08-20T03:25:35Z 2020-08-20T03:25:35Z 2018 Journal Article Ghimire, P. C., Bhattarai, A., Schweiss, R., Scherer, G. G., Wai, N., & Yan, Q. (2018). A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements. Applied Energy, 230, 974-982. doi:10.1016/j.apenergy.2018.09.049 0306-2619 https://hdl.handle.net/10356/143309 10.1016/j.apenergy.2018.09.049 230 974 982 en Applied Energy © 2018 Elsevier. All rights reserved. This paper was published in Applied Energy and is made available with permission of Elsevier. application/pdf
spellingShingle Engineering::Materials
Vanadium Redox Flow Battery
Electrode Compression
Ghimire, Purna C.
Bhattarai, Arjun
Schweiss, Rüdiger
Scherer, Günther G.
Wai, Nyunt
Yan, Qingyu
A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title_full A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title_fullStr A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title_full_unstemmed A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title_short A comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
title_sort comprehensive study of electrode compression effects in all vanadium redox flow batteries including locally resolved measurements
topic Engineering::Materials
Vanadium Redox Flow Battery
Electrode Compression
url https://hdl.handle.net/10356/143309
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