Seal Connection Geometry for Uniform Gas Diffusion Layer Penetration
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Solution Overview
Problem
The production and installation of edge reinforcement arrangements for seals in electrochemical devices are complex and cost-intensive, and the use of these arrangements reduces the volumetric power density due to additional installation space requirements, while direct connection of seals to gas diffusion layers can lead to uneven penetration and mechanical damage during the injection molding process.
Innovation Solution
Designing the connection area between the distribution area and the connection area as a bottleneck with high flow resistance ensures uniform penetration of the gas diffusion layer by the sealing material, using a large flow cross-section distributor area and a thin connection area to minimize internal pressure and prevent excessive penetration, and incorporating a flexible connection area to compensate for thermal expansion and shrinkage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a seal is directly connected to a gas diffusion layer using injection molding, then the production and installation process is simplified and costs are reduced, but the sealing material penetrates unevenly into the gas diffusion layer causing mechanical damage
Solution Approach 1:
The seal is designed with a connection area that has locally differentiated properties: a first region with higher cross-linking density and stiffness for structural support, and a second region with lower cross-linking density for controlled penetration into the gas diffusion layer. This local quality differentiation enables both simplified direct connection and uniform penetration without mechanical damage.
Solution Approach 2:
The seal material's physical and chemical parameters are spatially varied through different cross-linking densities. The first region has higher cross-linking density providing stiffness, while the second region has lower cross-linking density allowing controlled penetration. This parameter change resolves the contradiction between ease of manufacture and manufacturing precision.
2Stability of the object's composition
If edge reinforcement arrangements are used to support seals, then mechanical stability is improved, but device complexity and production costs increase
Solution Approach 1:
The seal and edge reinforcement functions are merged into a single integrated seal component. The first region of the seal with higher cross-linking density provides the edge reinforcement function, eliminating the need for separate edge reinforcement arrangements. This reduces device complexity while maintaining mechanical stability.
Solution Approach 2:
The seal is designed as a multi-functional component that simultaneously provides sealing, edge reinforcement, and structural support. The differentiated regions of the seal perform multiple functions that were previously required separate components, thereby reducing overall device complexity.
3Strength
If the seal material penetrates deeply into the gas diffusion layer, then mechanical connection strength is improved, but the porous structure is damaged and gas diffusion performance deteriorates
Solution Approach 1:
The seal's second region is designed with lower cross-linking density specifically to control penetration depth and manner. This local quality difference allows the seal to penetrate sufficiently for strong mechanical connection while preventing excessive penetration that would damage the porous gas diffusion layer structure.
Solution Approach 2:
The differentiated cross-linking density in the seal acts as an intermediary mechanism that mediates between the need for strong mechanical connection and the need to preserve gas diffusion layer integrity. The controlled penetration through the second region achieves connection strength without causing harmful damage.
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 results in a more uniform and stable mechanical connection between the seal and the gas diffusion layer, reducing the risk of mechanical damage and maintaining the structural integrity of the electrochemical device while optimizing the injection molding process, leading to increased process reliability and reduced component distortion.
Implementation Method 1
the sealing material penetrates a part of the at least one gas diffusion layer
Implementation Method 2
the polymer material shrinks upon cooling
Implementation Method 3
the connection area between the distribution area and the connection area is designed as a bottleneck with high flow resistance
Data Source
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AI summary
The aim of the invention is to provide an electrochemically active unit for an electrochemical device, comprising a membrane electrode assembly, at least one gas diffusion layer and a seal, which is joined to at least one of the at least one gas diffusion layer, in the production of which electrochemically active unit the penetration region, in which the gas diffusion layer of the electrochemically active unit is penetrated by the seal material of the seal, can be formed as uniformly as possible along the periphery of the gas diffusion layer. This aim is achieved in that the seal comprises a joining region, a distributing region and a connecting region connecting the joining region and the distributing region to each other, the connecting region having a smallest height (hC) that is less than a fourth of the greatest height (HV) of the connecting region and less than a fourth of the greatest height (HA) of the joining region.