Numerical analysis of vanadium redox flow batteries considering electrode deformation under various flow fields
Journal article, 2023

The porous electrode of vanadium redox flow batteries (VRBs) is subject to deformation due to mechanical stress during stack assembling. The forces compress the electrode fiber into the flow channel and thus alter the electrode porosity ratio. Due to the complex mechanisms, the effects of resulting electrode morphological changes on VRB performance were usually ignored in existing studies. This paper proposes a three-dimensional VRB model considering the uneven electrode deformation to investigate the cell performance under different electrode compression ratios with three flow-field designs. Compression ratio (CR) and the intrusive part of the electrode are obtained under various mechanical stress by adjusting gasket thickness in the experiment. The proposed electrochemical model is established based on the comprehensive description of conservation laws and analyzed using the COMSOL platform. Three indices, namely the concentration overpotential, pressure drop, and distribution uniformity, are selected for the analysis under the three flow field designs and different CRs. The numerical study reveal that the pressure drop and the concentration overpotential are sensitive to the CR but less affected by the concentration uniformity. The minimum overpotential can be reached when the CR is around 40%–50%, depending on flow field designs, while a higher CR can cause a drastically increased pressure drop. It is also found that the interdigitated flow field with a CR of 45% is considered optimal. The insights from the proposed method demonstrate the significance of considering the effects of electrode deformation in the stack design under various flow fields.

Numerical study

Vanadium redox flow battery

Uneven electrode deformation

Battery design

Flow channel

Electrochemical model

Author

Binyu Xiong

Wuhan University of Technology

Yang Li

Chalmers, Electrical Engineering, Systems and control

Yuming Ding

Wuhan University of Technology

Jinsong Wang

Case Western Reserve University

Zhongbao Wei

Beijing Institute of Technology

Jiyun Zhao

City University of Hong Kong

Xiaomeng Ai

Huazhong University of Science and Technology

Jiakun Fang

Huazhong University of Science and Technology

Journal of Power Sources

0378-7753 (ISSN)

Vol. 564 232814

Subject Categories

Aerospace Engineering

Applied Mechanics

Fluid Mechanics and Acoustics

DOI

10.1016/j.jpowsour.2023.232814

More information

Latest update

3/16/2023