Redox Flow Battery Shunt Current Reduction via Gas Injection
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Solution Overview
Problem
Conventional redox flow batteries suffer from shunt currents, which reduce their cycle lifetime and energy efficiency, and existing solutions either increase electrolyte flow resistance or lead to power losses and instability.
Innovation Solution
A system that injects gas into the inlet and outlet ducts of redox flow battery cells to form gas bubbles, which are then removed before entering the compartments, creating electrical insulation and reducing shunt currents without affecting power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional redox flow batteries are configured with cells electrically connected in series and electrolyte passing through via parallel pathways, then high voltage levels and high capacities are achieved, but shunt currents appear that reduce cycle lifetime and energy efficiency
Solution Approach 1:
Gas bubbles are introduced as an intermediary substance into the electrolyte flow paths. These bubbles act as a mediator that disrupts the continuous conductive path of the electrolyte, thereby blocking shunt currents without interfering with the electrochemical reactions in the cells. The gas bubbles are injected at controlled locations and removed before the electrolyte enters the compartments, serving as a temporary barrier against harmful currents.
2Loss of energy
If existing solutions are used to reduce shunt currents, then shunt current is decreased, but electrolyte flow resistance increases or power losses occur
Solution Approach 1:
The invention utilizes pneumatic principles by injecting gas into the liquid electrolyte flow paths. This creates gas bubbles that rise and coalesce, forming temporary barriers to ionic conduction. The gas injection system uses controlled pressure and flow rates to generate bubbles of appropriate size and distribution, achieving shunt current reduction through fluid dynamics rather than mechanical or electrical means that would increase resistance or power consumption.
3Loss of energy
If gas bubbles are injected into inlet and outlet ducts to form electrical insulation, then shunt currents are reduced, but device complexity increases
Solution Approach 1:
The gas bubble removal system is designed to operate passively using natural buoyancy forces. Gas bubbles, being less dense than the electrolyte, automatically rise to the surface and are removed through strategically positioned outlets or breakers. This self-service mechanism eliminates the need for active pumping or complex mechanical removal systems, reducing overall device complexity while maintaining effective shunt current reduction.
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
This approach effectively reduces or eliminates shunt currents, maintaining high power efficiency and extending the battery's useful life by preventing energy loss and corrosion.
Implementation Method 1
injecting gas into the inlet and outlet ducts of cathode and anode compartments of (n−1) electrochemical cells in order to form gas bubbles in the inlet and outlet ducts
Implementation Method 2
a device for removing the gas bubbles which is positioned on the inlet ducts of the cathode and anode compartments of the (n−1) electrochemical cells
Data Source
AI summary
The invention is a redox flow battery (1000) comprising n electrochemical cells 300 that are electrically connected in series (300) with each cell including a cathode (310) and an anode (320) that are separated by a membrane (330) and that are respectively passed through by a catholyte and an anolyte originating from a catholyte tank (110) and an anolyte tank (120). The cells are fluidically connected in parallel. The invention is also a system for decreasing bi-pass currents including means (700) for injecting a gas into the inlet ducts (401) and outlet ducts (501) of the cathode and anode of (n−1) cells to form gas bubbles; and a device (800) for removing the gas bubbles, placed, on the inlet ducts of the cathode and anode of the (n−1) cells, downstream of the means for injecting the gas and upstream of the cathode and anode of the cells.