Interconnected Tank Pipes for Vanadium Redox Flow Battery Level Control
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Solution Overview
Problem
Existing methods for maintaining a desired liquid level between tanks in vanadium redox flow batteries, such as using a single open pipe for fluid communication, are prone to airlocks and syphoning issues, especially when one tank ruptures, leading to electrolyte mixing and capacity loss.
Innovation Solution
A system comprising a lower tank connection pipe connected below the desired fluid level, an upper tank connection pipe connected above the level, and an inter-pipe connecting pipe, which minimizes stagnant volume, prevents rapid mixing, and allows for gas movement to prevent syphoning, with the upper pipe acting as an overflow and accommodating varying fill levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single open pipe is used to maintain fluid communication between tanks, then the system is simple and inexpensive, but electrolyte will be syphoned from one tank to another if one tank ruptures, increasing the volume to be spilt and the heat resultant from mixing
Solution Approach 1:
The single open pipe is segmented into two separate pipes: a upper pipe connected above the normal liquid levels and a lower pipe connected below the normal liquid levels. This segmentation prevents syphoning during tank rupture while maintaining fluid communication during normal operation, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The solution transitions from a single-dimensional (one pipe) to a two-dimensional (two pipes at different heights) configuration. The upper and lower pipes work together to provide both normal operation functionality and rupture protection, addressing the reliability issue without significantly increasing complexity.
2Device complexity
If a single open pipe is used to maintain fluid communication between tanks, then the system is simple and inexpensive, but the pipe is liable to suffer from airlocks, especially when initially filling and during operation as dissolved gases are released
Solution Approach 1:
The single pipe is divided into upper and lower segments that are connected indirectly through the tank system. This segmentation allows air to be trapped and managed in each segment separately, preventing airlocks from blocking the entire fluid communication path while maintaining system simplicity.
Solution Approach 2:
The tank system acts as an intermediary between the upper and lower pipes, allowing air to be accommodated and released through the tank openings rather than blocking the pipe flow. This intermediary arrangement prevents airlocks while maintaining the simple two-pipe configuration.
3Reliability
If an overflow pipe is used to connect the electrolyte tanks, then fluid level imbalance can be corrected, but there is inherently an imbalance in fluid levels requiring loss of capacity
Solution Approach 1:
The lower pipe connects the tanks at equal potential levels (below normal liquid levels), allowing fluid to flow freely between tanks without creating level imbalances. This eliminates the need for overflow mechanisms that cause capacity loss, resolving the contradiction between fluid level balance and electrolyte retention.
Solution Approach 2:
The lower pipe enables the system to self-regulate fluid levels passively through gravity-driven flow, without requiring active pumping or overflow mechanisms that would result in electrolyte loss. The system maintains balance automatically while preserving capacity.
4Reliability
If the lower tank connection pipe is curved with a high point, then gas can be vented to prevent airlocks, but the pipe volume increases creating more stagnant electrolyte
Solution Approach 1:
The lower pipe includes a moderate curve with a high point that provides sufficient gas venting capability without creating excessive pipe volume. This partial implementation of curving achieves the necessary airlock prevention while minimizing stagnant electrolyte, balancing reliability and substance retention.
Solution Approach 2:
The pipe curvature is applied locally at specific sections where gas accumulation is most likely, rather than curving the entire pipe length. This localized curving provides effective air venting while minimizing the overall stagnant volume in the pipe system.
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 maintains consistent electrolyte levels between tanks, reduces the risk of syphoning and electrolyte mixing, and allows for flexible fill levels without precise control, enhancing the operational efficiency and safety of vanadium redox flow batteries.
Implementation Method 1
If one of the tanks ruptures, electrolyte will be syphoned from the other tank, through the connecting pipe until the liquid level is below the connecting pipe
Implementation Method 2
the upper tank connection pipe is connected to both the first and second tanks above the normal liquid levels
Data Source
AI summary
Means for maintaining level complementary electrolytes inflow battery tanks has first and second interconnected tanks 2, 3. The first tank 2 contains positive electrolyte, 2b, and the second tank containing negative electrolyte 3b. Both tanks have a void 2a and 3 a respectively, for air or other noble gases. The tanks themselves are connected by pipes; a lower tank connecting pipe 4, an upper tank connection pipe 5 with an inter-pipe connecting pipe 6 therebetween. The peak of the lower tank connection pipe 4a is designed to remain below the normal liquid level 7 of both tanks, in contrast to the upper tank connection pipe 5 which remains above the desired liquid level 7.