Tortuous Flow Battery Manifold Reduces Shunt Currents
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Solution Overview
Problem
Flow battery systems face efficiency reductions due to induced electrical shunt currents between adjacent cells with different electrical potentials, which affect the overall performance of the system.
Innovation Solution
The flow battery stack system incorporates a tortuous configuration of passages in the manifold plates to reduce shunt current losses, featuring serpentine and counter-flow passage segments that increase resistance and induce a higher flow rate and pressure drop, thereby minimizing gas stagnation and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If flow battery cells are arranged in series with long parallel paths, then power and voltage are increased, but electrical shunt currents are induced between adjacent cells with different potentials, reducing system efficiency
Solution Approach 1:
The patent applies serpentine (curved) passage configurations instead of straight parallel paths. The tortuous, curved passages increase the electrical resistance between adjacent cells by extending the current path length and introducing geometric resistance, thereby reducing shunt current losses while maintaining the series electrical connection for high power and voltage output
2Ease of operation
If straight parallel paths are used through flow battery cells, then fluid flow is simplified, but gas stagnation occurs and flow rate is insufficient, reducing efficiency
Solution Approach 1:
The serpentine passages use curved configurations to prevent gas stagnation by creating continuous flow motion and eliminating dead zones where gas could accumulate. The curved paths maintain relatively simple fluid operation while significantly improving flow rate and preventing stagnation through geometric design
Solution Approach 2:
The passage is divided into multiple segments (serpentine sections) that create a stepwise flow path. This segmentation prevents gas accumulation by ensuring continuous movement through each segment, while maintaining manageable flow characteristics similar to straight paths
3Speed
If low resistance paths are used in manifold plates, then flow rate is increased, but pressure drop is insufficient and shunt currents are not effectively reduced
Solution Approach 1:
The serpentine passages achieve an optimal balance by using curved paths that extend the flow length (increasing resistance to shunt currents) while maintaining adequate flow rate. The curvature creates sufficient pressure drop to reduce shunt currents without completely restricting the main fluid flow through the battery cells
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 configuration effectively reduces shunt current losses and improves the efficiency of the flow battery system by maximizing resistance and flow rate, ensuring better performance and energy storage capabilities.
Implementation Method 1
The flow battery cells may be serially connected to increase power and voltage of the flow battery system. The anolyte and catholyte solutions typically flow in relatively long and parallel paths through the cells. Electrical shunt currents may be induced within the solutions where, for example, adjacent flow battery cells have different electrical potentials. Such shunt currents may reduce efficiency of the flow battery system.
Implementation Method 2
The flow battery stack system incorporates a tortuous configuration of passages in the manifold plates to reduce shunt current losses, featuring serpentine and counter-flow passage segments that increase resistance and induce a higher flow rate and pressure drop, thereby minimizing gas stagnation and enhancing efficiency.
Data Source
Figure 1
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AI summary
A flow battery stack includes an inlet manifold, an outlet manifold and a plurality of flow battery cells. The inlet and outlet manifolds each have first and second passages. The first and second passages in at least one of the inlet and outlet manifolds are tortuous. Each flow battery cell includes a separator arranged between a first electrode layer and a second electrode layer. The flow battery cells are axially connected between the inlet manifold and the outlet manifold such that a first solution having a first reversible redox couple reactant is directed from the inlet first passage through the flow battery cells, wetting the first electrode layers, to the outlet first passage.