Fuel Cell Electrode Sealing Member Design

Solution Overview

Problem

Existing fuel cell electrode structures face issues with gas leakage due to poor sealing, especially when using metal separators, leading to decreased power generation efficiency and fuel efficiency, as the dimensional accuracy of gaskets is poor and the shape of the gasket does not conform well to the step between separators and electrodes, allowing reaction gas to escape through the periphery.

Innovation Solution

A fuel cell electrode structure with a sealing member that includes an extended portion thinner than the lip portion, which contacts the gas diffusion layer, and is compressed by metal separators to prevent gas leakage, ensuring the reaction gas flows on the reaction surface rather than through the periphery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a punched rubber gasket is used as a sealing member, then the sealing structure is simple, but the dimensional accuracy is poor and gaps are formed between the membrane electrode structure and the gasket

Engineering Contradiction:

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The sealing member is changed from a punched rubber gasket to an extruded rubber product with a specific L-shaped cross-section. This parameter change in the manufacturing method and geometry enables precise dimensional control while maintaining sealing effectiveness, eliminating the gap formation issue.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the sealing member shape is conformed to the step between separators and electrodes, then sealing is improved, but the device complexity increases

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sealing member is divided into two functional portions: an extended portion that fills the step between separators and electrodes to provide sealing, and a lip portion that contacts the gas diffusion layer to prevent gas leakage. This segmentation allows each portion to perform its specific function with a simplified geometry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing member is designed with an L-shaped cross-section, adding a vertical dimension to the sealing approach. The extended portion extends downward to fill the step, while the lip portion extends upward to contact the gas diffusion layer, creating a multi-dimensional sealing solution.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If metal separators are used, then the mechanical strength is improved, but it is difficult to form a sealing groove in the right angle

Engineering Contradiction:

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Instead of forming a sealing groove in the metal separator (which is difficult due to material hardness), the sealing member itself is given an L-shaped cross-section that naturally fits into the step structure. The sealing groove in the separator only needs to accommodate the extended portion, not form the complete sealing geometry.

Inventive Principle:

Principle #13The other way round (Inversion)

4Productivity

If narrow reaction gas channels are used, then the power generation performance is improved, but gas leakage through small gaps increases

Engineering Contradiction:

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The sealing member is made of rubber material that can be compressed between the metal separators. This flexible property allows the sealing member to deform and fill any gaps or irregularities in the assembly, providing reliable sealing even in narrow gas channel configurations where gap sealing is critical.

Inventive Principle:

Principle #30Flexible shells and thin films

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 effectively prevents gas leakage and enhances fuel cell efficiency by ensuring the sealing member contacts the gas diffusion layer, maintaining the reaction area and improving the sealing properties, even in narrow gas channels, thus boosting fuel economy and power generation.

Implementation Method 1

the sealing member is compressed by metal separators to prevent gas leakage

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

a sealing member disposed on the frame and sealing the periphery of the membrane electrode assembly

Methodology Applied

Scientific EffectPhysical Containment: Physical Containment

Data Source

PatentEP3309885B1Fuel cell electrode structure, metal separator, fuel cell employing said fuel cell electrode structure and said metal separator, and die for fabricating said fuel cell electrode structure

Publication Date: 2021.03.31

Figure 1
Figure 2(a)~2(b)
Figure 3~4

AI summary

A fuel cell electrode structure includes a membrane electrode assembly including an electrolyte membrane between a pair or electrodes, and a frame being integrally formed with the membrane electrode assembly supporting the membrane electrode assembly from the peripheral side. The membrane electrode assembly includes a gas diffusion layer on the surface, and a sealing member for sealing the periphery of the membrane electrode assembly is provided on the frame. The sealing member includes a lip portion, and at least partly includes extended portion that extends to the membrane electrode assembly. The extended portion is thinner than the lip portion of the sealing member, and the end face of the extended portion is in contact with the end face of the gas diffusion layer.