Multi-Stage Rebalancing Reactor for Redox Flow Battery Charge Balance
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Solution Overview
Problem
Conventional redox flow batteries face issues with electrolyte state of charge imbalance due to hydrogen generation from side reactions, leading to reduced battery capacity and electrolyte stability problems.
Innovation Solution
A multi-stage rebalancing reactor system is introduced, featuring individually housed reactor vessels with catalyst beds, where each stage is fluidly coupled to adjacent stages, facilitating the reduction of ions and oxidation of gases to restore electrolyte balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrochemical rebalancing cell is used, then the system structure is simple, but the catalyst bed efficiency is reduced due to height control and positioning issues
Solution Approach 1:
The patent divides a single large rebalancing cell into multiple smaller stages, each with its own catalyst bed. This segmentation allows each catalyst bed to maintain optimal height and positioning, maximizing reaction efficiency while distributing the overall rebalancing function across multiple units. The staged configuration ensures that hydrogen gas and electrolyte maintain proper contact with catalyst surfaces in each stage, preventing the efficiency losses associated with single-cell designs.
2Productivity
If the catalyst bed height is increased to improve reaction rate, then the productivity increases, but the device complexity and positioning control requirements increase
Solution Approach 1:
Instead of using one tall catalyst bed that requires complex positioning control, the patent segments the rebalancing function into multiple shorter stages. Each stage has a compact catalyst bed with simplified positioning requirements, while collectively achieving the same or higher overall reaction rate through parallel or series configuration of multiple stages.
Solution Approach 2:
The patent transitions from a single vertical dimension (one tall catalyst bed) to multiple vertical dimensions (multiple stacked stages), effectively distributing the reaction volume across different height levels. This dimensional redistribution simplifies the positioning control of individual catalyst beds while maintaining high overall productivity.
3Ease of operation
If hydrogen gas is not removed from the electrolyte, then the system operation is simple, but the electrolyte state of charge becomes imbalanced and battery capacity decreases
Solution Approach 1:
The rebalancing reactor is designed to automatically remove hydrogen gas from the electrolyte through electrochemical reactions at the catalyst beds, converting dissolved hydrogen back into protons. This self-service function continuously maintains electrolyte state of charge balance without requiring external intervention or complex monitoring systems, thus preserving operational simplicity while ensuring reliability.
Solution Approach 2:
The multi-stage rebalancing reactor provides continuous feedback-based hydrogen removal, where the electrochemical reactions in each stage respond to the presence of dissolved hydrogen and adjust the rebalancing rate accordingly. This automatic feedback mechanism maintains electrolyte balance without requiring complex external control systems.
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 multi-stage rebalancing reactor effectively maintains the capacity of redox flow battery systems by restoring electrolyte balance, thereby enhancing battery performance and stability.
Implementation Method 1
Electrochemical reactions occurring at the electrodes of the rebalancing cell convert gaseous hydrogen back to protons
Implementation Method 2
Electrochemical reactions occurring at the electrodes of the rebalancing cell convert gaseous hydrogen back to protons
Implementation Method 3
Redox flow batteries store electrical energy in a chemical form and subsequently dispense the stored energy in an electrical form via a spontaneous reverse redox reaction
Data Source
AI summary
A method for a redox flow battery system may include flowing an electrolyte from an electrolyte storage tank to a multi-stage rebalancing reactor, the multi-stage rebalancing reactor comprising reactor vessels grouped to form stages. Hydrogen gas may be injected into the electrolyte upstream of the multi-stage rebalancing reactor via a gas line and a metal ion of the electrolyte may be chemically reduced by oxidizing the hydrogen gas at a catalyst bed of each of the reactor vessels to maintain a charge balance of the electrolyte and a pH of the electrolyte within a predetermined range.