Porous electrode stacks, flow half cells and flow battery stacks

Abstract

The invention provides a porous electrode group, a liquid flow half-cell and a liquid flow cell stack. The porous electrode group comprises a plurality of overlaid porous electrodes, wherein at least two porous electrodes are flow channel electrodes provided with flow channels, and parts of at least two flow channel electrodes are communicated and form a flow field. The flow field which is formed by mutually communicating flow channels and for flow of electrolyte is arranged inside at least one porous electrode of the porous electrode group. Due to the fact the electrolyte flows in the porous electrodes under the flow guidance of the flow field, superficial area which the electrolyte osmoses to material parts of the porous electrodes is enlarged, liquid flow resistance to the flow of the electrolyte caused by the porous electrodes is reduced, and liquid flow differential pressure needed by the flow of the electrolyte is reduced effectively. Besides, due to the fact that the electrolyte evenly osmoses to the porous electrodes on two sides of the flow field when the electrolyte flows in the flow field, liquid flow uniformity is increased, concentration polarization caused by uneven flow of the electrolyte is reduced, and charging and discharging efficiency of liquid flow cells with the porous electrode group, the liquid flow half-cell and the liquid flow cell stack is improved.

Description

technical field [0001] The invention relates to the field of liquid flow battery design, in particular to a porous electrode group, a liquid flow half-cell and a liquid flow battery stack. Background technique [0002] The all-vanadium redox flow battery is an electrochemical reaction device that performs redox with vanadium ion electrolytes in different valence states, and can efficiently realize the mutual conversion between chemical energy and electrical energy. This type of battery has the advantages of long service life, high energy conversion efficiency, good safety, and environmental friendliness. It can be used in large-scale energy storage systems for wind power generation and photovoltaic power generation. It is the main choice for power grid peak shaving and valley filling and load balancing one. Therefore, in recent years, all-vanadium redox flow batteries have gradually become the focus of research on large-capacity energy storage batteries. [0003] All-vanad...

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Problems solved by technology

[0004] The flow of electrolyte in the existing flow battery stack generally depends on the permeation and mass transfer of porous electrodes. The efficiency of the battery system is reduced; on the other hand, the electrolyte flow inside the battery stack is uneven and the concentration polarization is large, which causes the internal loss of the battery stack, thereby reducing the voltage efficiency of the battery

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