Fe-Cr Redox Flow Battery Electrolyte Balance for Low Hydrogen Generation
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Solution Overview
Problem
Existing technologies for energy storage and renewable power generation have limitations in managing intermittent renewable energy sources and require an affordable and reliable energy storage system.
Innovation Solution
A redox flow battery system utilizing Fe-Cr redox chemistry with controlled molar ratios of chromium and iron in electrolytes to manage hydrogen generation and maintain storage capacity over multiple charge/discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional energy storage systems are used, then energy storage capacity can be achieved, but hydrogen generation occurs causing degradation and reduced system life
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by using specific molar ratios of chromium (III) to iron (II) salts (greater than 0.5:1), and controlling the concentration ranges of these salts. This parameter optimization suppresses hydrogen generation while maintaining energy storage capacity, thereby improving system reliability and lifespan.
Solution Approach 2:
The patent converts the potentially harmful hydrogen generation side reaction into a beneficial outcome by optimizing the electrolyte composition. The controlled hydrogen evolution actually helps maintain the redox balance and prevents more severe degradation, turning a harmful factor into one that contributes to long-term system stability.
2Power
If renewable power generation is increased, then energy supply capacity is improved, but intermittency causes mismatch with user load demand
Solution Approach 1:
The redox flow battery system enables continuous energy storage and discharge operations. The electrolyte circulation system continuously pumps electrolyte between storage tanks and the electrochemical cell, allowing the system to continuously charge during renewable energy surplus and discharge during demand periods, bridging the intermittency gap.
Solution Approach 2:
The battery system serves multiple functions: it stores energy from intermittent renewable sources, provides stable power output matched to user demand, and maintains electrolyte balance through the redox reactions. This multi-functionality allows it to address both the capacity and stability requirements of renewable energy integration.
3Quantity of substance
If chromium and iron salt concentrations are increased, then energy storage capacity is improved, but hydrogen generation increases causing degradation
Solution Approach 1:
The patent optimizes the concentration parameters of chromium (III) and iron (II) salts within specific ranges (0.5-2.0 M for chromium, 0.5-2.0 M for iron) and maintains a molar ratio greater than 0.5:1. This parameter optimization achieves high energy storage capacity while suppressing excessive hydrogen generation that would cause degradation.
Solution Approach 2:
The system maintains a balanced electrolyte composition where the chromium (III) to iron (II) molar ratio acts as a feedback mechanism. When hydrogen generation becomes excessive, the redox balance shifts, and the controlled composition ensures the system self-regulates to prevent degradation while maintaining capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Fe-Cr redox flow battery system maintains storage capacity with minimal hydrogen generation, achieving long life and efficient energy storage with reduced degradation over 100-500 cycles.
Implementation Method 1
redox flow battery system utilizing Fe-Cr redox chemistry
Implementation Method 2
Production of electrolytes can include a combination of chemical reduction and electrochemical reduction
Data Source
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AI summary
A system includes a redox flow battery system that includes an anolyte, a catholyte, a first half-cell having a first electrode in contact with the anolyte, a second half-cell having a second electrode in contact with the catholyte, and a first separator separating the first half-cell from the second half-cell. The system also includes a balance arrangement that includes a balance electrolyte having vanadium ions in solution, a third half-cell having a third electrode in contact with the anolyte or the catholyte, a fourth half-cell having a fourth electrode in contact with the balance electrolyte, and a reductant in the balance electrolyte or introducible to the balance electrolyte for reducing dioxovanadium ions.