Fuel Cell Seal Structure Balancing Tightness and Pressing Stability

Solution Overview

Problem

Soft sealants used in fuel cells increase permeability, compromising media tightness and requiring unstable pressing processes, which affects the long-term sealing function.

Innovation Solution

A sealing method using a filler material with lower hardness than the external sealant to create a hollow or filled seal, allowing for a hard, permeation-tight sealant while maintaining tolerance robustness through a stable pressing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If soft sealants are used to enable stable pressing process control, then ease of operation is improved, but permeability increases which worsens media tightness

Engineering Contradiction:

Improvepressing process controlVSAvoidpermeability

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The seal is divided into two functional parts: an outer sealant layer and an inner filler material. The outer sealant (e.g., EPDM, FKM, TPE) provides media tightness and structural integrity, while the inner filler material (softer, Shore hardness <30 ShA) provides pressing stability and tolerance compensation. This segmentation allows each material to optimize its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite seal structure combining two materials with different hardness properties. The outer sealant has higher hardness for permeation tightness, while the inner filler has lower hardness for pressing process stability. This composite approach resolves the contradiction by integrating the advantages of both material types into a single functional seal.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If hard sealants are used to reduce permeability, then media tightness is improved, but pressing process stability deteriorates

Engineering Contradiction:

ImprovepermeabilityVSAvoidpressing process control

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The seal is divided into two functional parts: an outer sealant layer and an inner filler material. The outer sealant (e.g., EPDM, FKM, TPE) provides media tightness and structural integrity, while the inner filler material (softer, Shore hardness <30 ShA) provides pressing stability and tolerance compensation. This segmentation allows each material to optimize its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite seal structure combining two materials with different hardness properties. The outer sealant has higher hardness for permeation tightness, while the inner filler has lower hardness for pressing process stability. This composite approach resolves the contradiction by integrating the advantages of both material types into a single functional seal.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If soft sealants are used to increase tolerance robustness, then adaptability is improved, but long-term sealing function deteriorates due to fatigue

Engineering Contradiction:

Improvetolerance robustnessVSAvoidsealing function durability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The seal is divided into two functional parts: an outer sealant layer and an inner filler material. The outer sealant (e.g., EPDM, FKM, TPE) provides media tightness and structural integrity, while the inner filler material (softer, Shore hardness <30 ShA) provides pressing stability and tolerance compensation. This segmentation allows each material to optimize its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the seal have different material properties optimized for their specific functions. The outer region uses hard, fatigue-resistant sealant for long-term durability and media tightness, while the inner region uses soft, compliant filler material for tolerance compensation and pressing stability. Each local region has the quality it needs for its specific role.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240387840A1Method for producing a seal, sealing arrangement with seal, fuel cell and fuel cell stack

Publication Date: 2024.11.21 ROBERT BOSCH GMBH

AI summary

The invention relates to a method for producing a seal (1) between two joining partners, preferably between a bipolar plate (2) and a membrane electrode arrangement (3) of a fuel cell, in which at least one sealant (4) is applied to one of the two joining partners. According to the invention, the seal (1) is hollow or filled with a filler material (5), wherein a filler material (5) is used which has a lower hardness, in particular Shore hardness, compared to the outer sealant (4).The invention also relates to a sealing arrangement, a fuel cell with a sealing arrangement according to the invention and a fuel cell stack.