Fuel Cell Stack Tensioning for End Plate Compression Stability
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Solution Overview
Problem
Existing fuel cell stacks face challenges in maintaining uniform compression and preventing end plate deformation, particularly around inlet and outlet openings, due to the aging of elastic tensioning elements and the need for additional installation space for compression springs, which can lead to stress peaks and reduced sealing effectiveness.
Innovation Solution
A fuel cell stack design incorporating both first and second elastic tensioning elements, where the first elements provide overall bracing and the second elements specifically target end plate regions, with adjustable torsion springs and rotatable mounting shafts to ensure precise re-tensioning and maintain compression over time, preventing end plate bending and blocking of openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If elastic tensioning elements are used to compress the fuel cell stack, then the stack compression is maintained, but the elastic elements age and lose tension over time
Solution Approach 1:
The patent introduces adjustable and re-tensionable tensioning elements that can be dynamically adjusted to maintain compression force. The tensioning elements include adjustment mechanisms allowing operators to re-tension them during operation, transforming the static compression system into a dynamic one that can compensate for aging effects and maintain reliable sealing over extended periods.
2Stress or pressure
If compression springs are added to compensate for stack expansion, then stress peaks are prevented, but additional installation space is required
Solution Approach 1:
The patent combines the functions of compression springs and tensioning elements into an integrated system. The tensioning elements work in conjunction with the springs to provide both stress peak prevention and compression maintenance, eliminating the need for separate installation spaces for these components and optimizing the overall stack volume.
3Shape
If tensioning elements are positioned near inlet or outlet openings, then end plate bending is prevented, but the openings may be blocked
Solution Approach 1:
The patent applies different tensioning strategies to different regions of the end plates. Tensioning elements are selectively positioned and configured based on local requirements - providing maximum support in areas prone to bending while maintaining clear pathways for inlet and outlet openings. This localized approach ensures structural integrity without compromising operational accessibility.
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 design ensures consistent and precise compression of the fuel cell stack, preventing end plate deformation and maintaining sealing integrity, even as elastic tensioning elements age, by allowing for automatic re-tensioning and reducing stress on the end regions, thus enhancing the operational lifespan and efficiency of the fuel cell stack.
Implementation Method 1
wherein a first end of the torsion spring, a first end of the at least one elastic tensioning element, and the mounting shaft are arranged in a first plane and a second end of the torsion spring, a second end of the at least one elastic tensioning element, and a longitudinal axis of the mounting shaft are arranged in a second plane extending perpendicularly to the first plane
Implementation Method 2
at least one elastic tensioning element which is tensioned between a first end plate and a second end plate in a stacking direction of the fuel cell stack
Data Source
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AI summary
The invention relates to a fuel cell stack (10) comprising a first end plate (51) and a second end plate (52) between which a plurality of fuel cells (11) is arranged. At least one tensioning or tensile element (55) is tensioned in the stack direction (S) between the end plates (51, 52). Inlets and outlets for operating media are arranged in first end regions (57) of the first end plate (51) and in second end regions (58) of the second end plate (52). According to the invention, at least one additional elastic tensioning element (60) is tensioned between first end regions (57) and/or second end regions (58) of the end plates (51, 52).