Fuel Cell Stack Compression Bands That Preserve Air Flow
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Solution Overview
Problem
Conventional fuel cell stack designs using external tie rods and compression mechanisms result in increased weight, volume, and complexity, compromising compressive forces and electrical contact, while air-cooled stacks face issues with air flow obstruction due to compression bands.
Innovation Solution
A fuel cell stack assembly utilizing continuous compression bands that wrap around protrusions on opposing faces of end plates in multiple passes, applying compressive force without blocking air channels, and using non-electrically conductive materials to prevent electrical shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If external tie rods are used to compress the fuel cell stack, then the stack can be held together with sufficient compressive force, but the weight and volume of the stack increase significantly
Solution Approach 1:
The patent employs a compression band that is substantially flexible and wraps around the peripheral edges of the fuel cell stack. This thin film approach replaces the rigid, heavy tie rods with a flexible band that can apply compressive force uniformly around the stack perimeter without adding significant weight or volume.
Solution Approach 2:
Instead of using linear tie rods that extend through the stack in one dimension, the invention transitions to a compression band that wraps around the stack in multiple dimensions, applying force circumferentially. This dimensional change allows for more efficient force distribution and reduced component size.
2Stability of the object's composition
If external tie rods are used to compress the fuel cell stack, then the stack can be maintained in its assembled state, but the overall volume of the stack increases
Solution Approach 1:
The compression band serves as a thin film structure that wraps tightly around the fuel cell stack, maintaining assembled state stability without requiring the additional volume needed for external tie rods, washers, and other fastening components.
Solution Approach 2:
The invention merges the functions of multiple separate fastening components (tie rods, washers, nuts, springs) into a single integrated compression band, thereby reducing the overall volume required for compression mechanisms while maintaining assembly stability.
3Stress or pressure
If the thickness of end plates is increased to evenly transmit compressive force, then the compressive force distribution improves, but the weight and volume of the stack increase
Solution Approach 1:
The flexible compression band distributes compressive force evenly around the peripheral edges of the stack without requiring thick end plates. The band's flexibility allows it to conform to the stack geometry and apply uniform pressure, eliminating the need for substantial end plate thickness.
4Force
If compression mechanisms with significant width are used, then sufficient compressive force can be applied, but air flow channels become obstructed in air-cooled stacks
Solution Approach 1:
The substantially flexible compression band has minimal width and wraps around the peripheral edges of the stack, positioning the compression force at the outermost boundaries. This thin film approach ensures that air flow channels remain unobstructed while still applying sufficient compressive force to maintain stack integrity.
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
Reduces weight and volume, enhances power density, efficiency, and lowers manufacturing costs by ensuring uniform compression and maintaining air flow, suitable for air-cooled stacks in portable devices.
Implementation Method 1
a substantially flexible compression band that has been tensioned to compress the stack in an assembled state
Data Source
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AI summary
A fuel cell stack assembly is disclosed comprising: a fuel cell stack comprising a first end plate, a second end plate, and a plurality of fuel cells interposed between the first and the second end plates; and a compression band which urges the first end plate towards the second end plate along a first face of the fuel cell stack and also along an opposing second face of the fuel stack in a stacking direction thereof in at least two passes on each face of fuel cells stack, thereby applying a compressive force upon the plurality of fuel cells in the fuel cell stack.