Redox Flow Battery Frame with Segmented Channels
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Solution Overview
Problem
Redox flow batteries experience significant shunt current loss between unit stacks, leading to self-discharge and reduced energy efficiency due to the low operating voltage and inefficient electrolyte distribution.
Innovation Solution
A flow frame design with a plate-like frame body, strategically positioned through holes, and a flow channel structure that connects diagonal through holes via an electrode hole, featuring a branch point with minimal cross-sectional area change, optimizing electrolyte distribution and reducing shunt current loss without additional control apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells are stacked in series to increase operating voltage, then operating voltage is improved, but shunt current loss increases due to electrolyte sharing between cells
Solution Approach 1:
The flow frame is divided into separate flow channels for each cell, with individual inlet and outlet channels. This segmentation prevents electrolyte from flowing between cells through shared channels, thereby eliminating shunt current loss while maintaining series connection for high voltage operation.
Solution Approach 2:
Each cell is provided with dedicated flow channels having specific inlet and outlet positions tailored to that cell's electrode configuration. This local optimization ensures electrolyte flows only through the intended cell pathways, preventing cross-cell shunt currents while maintaining efficient electrolyte distribution within each cell.
2Productivity
If through channels are added to improve electrolyte distribution, then electrolyte distribution is improved, but shunt current paths increase between stacks
Solution Approach 1:
The harmful function of through channels creating shunt current paths is extracted and eliminated. Instead of allowing electrolyte to flow through the frame body between stacks, the design uses dedicated flow channels confined to each cell, removing the shunt current pathway while preserving electrolyte distribution functionality.
Solution Approach 2:
Individual flow channels act as intermediaries that guide electrolyte flow exclusively within each cell boundaries. These channels mediate between the inlet/outlet ports and the electrodes, ensuring electrolyte distribution occurs without creating pathways for shunt current between adjacent stacks.
3Productivity
If flow channels are designed with branch points to distribute electrolyte, then electrolyte distribution is improved, but cross-sectional area changes cause flow instability
Solution Approach 1:
The design optimizes the cross-sectional area parameters of flow channels to minimize changes at branch points. By controlling the geometric parameters (cross-sectional area ratio close to 1:1), the flow stability is maintained while still achieving effective electrolyte distribution to multiple electrodes through the branch points.
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 flow frame effectively reduces shunt current loss and improves energy efficiency by evenly distributing electrolytes and increasing shunt resistance, thereby minimizing self-discharge in redox flow batteries.
Implementation Method 1
a flow channel disposed at a front of the frame body above and below the electrode hole so that two of the through channels diagonal to each other as a pair are connected to each other via the electrode hole
Implementation Method 2
The cathode cell 102A and the anode cell 102B are separated by an ion exchange membrane 104 through which ions can pass
Implementation Method 3
In the cathode cell 102A, electrons move through an electrode 106 in accordance with the operation of a power source/load 118, such that an oxidation/reduction reaction occurs
Data Source
AI summary
A flow frame for a redox flow battery includes: a frame body having a plate-like shape and an electrode hole in its center where an electrode is to be disposed; four through holes disposed at corners of the frame body, respectively; a flow channel disposed at a front of the frame body above and below the electrode hole so that two of the through channels diagonal to each other as a pair are connected to each other via the electrode hole; through channels disposed at distal ends of the flow channel to cause electrolyte flows toward a rear of the frame body; and a distribution channel connecting the through channels with the electrode hole at the rear of the frame body. The flow channel has at least one branch point, and a change in cross sectional area of the flow channel before and after the branch point is 10% or less.