Alkaline Fuel Cell Electrolyte Flow Plate for Ionic Leakage Control
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Solution Overview
Problem
The existing alkaline fuel cell stacks face challenges in minimizing ionic current leakage between electrochemical cells, which reduces power output, due to the limitations in designing electrolyte inflow and outflow tubes with high ionic resistance without causing over-pressurization of the electrolyte chamber, potentially leading to electrode flooding and damage.
Innovation Solution
The design incorporates a forward and rearward electrolyte flow plate assembly that creates an electrolyte inflow pipe with higher ionic resistance and an outflow pipe with a tapering recess to form an outflow funnel, ensuring even electrolyte flow and reducing leakage, while maintaining optimal pressure balance and preventing electrolyte from entering the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the length of the electrolyte outflow tube is increased and its cross-sectional area is reduced to increase ionic resistance, then ionic current leakage is reduced, but the electrolyte chamber becomes over-pressurized
Solution Approach 1:
The outflow tube is segmented into two distinct functional sections: an first outflow tube section with high ionic resistance (smaller cross-sectional area) to reduce leakage current, and a second outflow tube section with larger cross-sectional area to maintain proper pressure balance and prevent over-pressurization. This segmentation allows each section to optimize for its specific function without compromising the other.
Solution Approach 2:
Different sections of the outflow tube are given different local qualities - the first section has smaller dimensions optimized for high ionic resistance, while the second section has larger dimensions optimized for pressure regulation. This local differentiation resolves the contradiction by applying the appropriate geometric properties in the appropriate locations along the tube.
2Loss of energy
If the cross-sectional area of the electrolyte outflow tube is reduced to increase ionic resistance, then ionic current leakage is reduced, but the flow rate of electrolyte is restricted
Solution Approach 1:
The outflow tube is divided into two sections with different cross-sectional areas. The first section has a smaller area to provide high ionic resistance and reduce leakage, while the second section has a larger area to ensure sufficient electrolyte flow rate for heat removal and system productivity.
Solution Approach 2:
The tube structure varies locally along its length, with the upstream portion optimized for ionic resistance and the downstream portion optimized for flow capacity, allowing both contradictory requirements to be satisfied in different locations.
3Loss of energy
If the length of the electrolyte outflow tube is increased to increase ionic resistance, then ionic current leakage is reduced, but the thickness of the flow plate increases
Solution Approach 1:
Instead of uniformly increasing the length of the entire outflow tube, the invention applies increased ionic resistance locally in the first outflow tube section through reduced cross-sectional area, while keeping the overall tube length and flow plate thickness minimized through the second section's larger dimensions.
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 ionic current leakage, maintains the desired pressure within the electrolyte chamber, and ensures even electrolyte distribution across the chamber, enhancing the fuel cell stack's power output and longevity by preventing electrode damage.
Implementation Method 1
the electrolyte inflow pipe has a higher ionic resistance than the electrolyte outflow pipe
Implementation Method 2
The electrolyte flows through all of the electrochemical cells and their electrolyte chambers in parallel
Data Source
AI summary
An electrolyte chamber assembly (10) for an electrochemical cell 3, the assembly (10) comprising a forward electrolyte flow plate (8) and a rearward electrolyte flow plate 6 that are abutted with each other to form the assembly (10). The inward facing side of each flow plate (6, 8) is provided with an electrolyte inflow channel (15), an electrolyte outflow collector (34) and an electrolyte chamber aperture (14) that are mirror images of the electrolyte inflow channel (15), the electrolyte outflow collector (34) and the electrolyte chamber aperture (14) on the other flow plate (6, 8). The two electrolyte inflow channels (15) create together an electrolyte inflow pipe (16), the two electrolyte outflow collectors (34) create together an electrolyte outflow pipe 32 and the two electrolyte chamber apertures (14) create together an electrolyte chamber (19).