Variable Width Outflow Channel for Flow Battery Pressure Balancing
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Solution Overview
Problem
Flow batteries face challenges in regulating electrolyte solution circulation rates, leading to sub-optimal energy storage performance and limited cycle life due to varying back pressures across electrochemical cells, which complicates performance optimization.
Innovation Solution
Incorporating a variable width insert in the outflow channel of the electrochemical cell stack to adjust back pressure and circulation rates, allowing for more uniform electrolyte solution circulation by varying the width along the length of the channel, thereby leveling the pressure and circulation rates across cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolyte solution circulation is regulated through standard outflow channels, then the flow battery operates, but the back pressure varies across electrochemical cells leading to non-uniform circulation rates
Solution Approach 1:
The patent applies local quality by varying the width of the outflow channel at different positions to create different flow resistance characteristics in different regions. The outflow channel has a first width at a first position and a second width at a second position, with the ratio between these widths being between 0.5 and 2.0. This non-uniform width distribution creates localized pressure adjustments that compensate for the varying back pressures across different electrochemical cells, thereby achieving uniform circulation rates throughout the stack.
2Reliability
If the outflow channel width is kept uniform, then the device structure is simple, but the circulation rate cannot be leveled across cells with different back pressures
Solution Approach 1:
The patent implements local quality by introducing a non-uniform width profile in the outflow channel. The channel width varies along its length, with specific width ratios (0.5-2.0) between different positions, creating localized flow resistance variations that adapt to the back pressure distribution across the electrochemical cell stack. This resolves the contradiction by making the channel structure slightly more complex only where needed to achieve circulation uniformity.
Data Source
AI summary
The present disclosure is directed to methods for levelizing circulation rates over multiple electrochemical cells of an electrochemical cell stack due to a pressure drop that occurs at an outlet of each electrochemical cell.