Deformable Spacer Controls PEM Fuel Cell Seal Thickness
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Solution Overview
Problem
Existing sealing methods in fuel cell stacks, such as cure-in-place and form-in-place techniques, face challenges in reliably meeting tight gasket height tolerances and controlling the thickness of seals, leading to inefficiencies and increased cycle times.
Innovation Solution
The use of deformable spacers made from resilient materials like silicone elastomers or thermoplastics, which are integrated into the sealant to control the thickness of the seal during assembly and maintain sealing force, allowing for precise control of the distance between components and accommodating changes due to temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If form-in-place sealing is used to reduce cycle time and cost, then productivity improves, but manufacturing precision deteriorates due to inability to control uncured gasket thickness
Solution Approach 1:
A deformable spacer is introduced as an intermediary element between the sealant and the second component. The spacer has a defined thickness that directly controls the gasket height, acting as a physical mediator that transfers the thickness specification from the design stage to the assembled product without requiring precise control of the uncured sealant itself.
Solution Approach 2:
The invention changes the physical state parameter of the thickness control mechanism. Instead of controlling the thickness of the uncured sealant (which is difficult), the thickness is controlled through a solid deformable spacer with a precisely defined dimension. The spacer's thickness parameter becomes the primary control variable for gasket height.
2Manufacturing precision
If cure-in-place sealing is used to achieve tight gasket height tolerances, then manufacturing precision improves, but productivity deteriorates due to slow robotic dispensing speeds
Solution Approach 1:
The sealing system is segmented into distinct functional elements: the sealant provides the sealing material, while the deformable spacer provides the thickness control function. This segmentation allows each element to be optimized independently - the spacer for precision and the sealant for sealing performance - without being constrained by the limitations of a single integrated approach.
3Strength
If metal bipolar plates are used in fuel cell stacks, then electrical conductivity improves, but sealing reliability deteriorates due to insufficient plate stiffness and flatness for controlling uncured gasket thickness
Solution Approach 1:
The deformable spacer serves as a mediator between the metal bipolar plates and the sealant. It compensates for the plates' insufficient stiffness and flatness by providing its own defined thickness, ensuring consistent gasket height even when the metal plates vary in dimensional stability during the sealing process.
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 approach enables precise control of seal thickness and sealing force, reducing cycle times and costs by allowing for more flexible and efficient sealing processes while maintaining effective sealing performance, even under varying conditions.
Implementation Method 1
deformable spacers made from resilient materials like silicone elastomers or thermoplastics, which are integrated into the sealant to control the thickness of the seal during assembly and maintain sealing force
Implementation Method 2
The compression system compresses the seal between the first component and the second component and deforms the deformable spacer
Data Source
AI summary
A sealed assembly is made using sealant including a deformable spacer to control thickness without adversely impacting elasticity and sealing force. Deformable spacers (e.g., elastomer, polyolefin, etc.) are mixed with an elastomeric precursor material and dispensed onto an assembly component, such as a fuel cell bipolar plate, and the remaining component(s) are assembled by pressing against the deformable spacer to ensure a defined seal thickness. The precursor is cured to form a seal that is further compressed to provide an effective sealing force. The deformable spacers control the thickness of a sealed area and allow use of form-in-place sealing processes.