Fuel Cell Dummy Cell Sealing for Balanced Gas Flow Pressure

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Solution Overview

Problem

The existing fuel cell stacks face performance degradation due to differential pressure imbalances between reaction cells and dummy cells, leading to reduced flow rates and discharge issues, as the dummy cell's larger gas flow paths result in lower reaction gas pressure, causing inefficiencies in the fuel cell stack.

Innovation Solution

A dummy cell design with airtight adhesive applied between dummy gas diffusion layers and sealing gaskets, restricting reaction gas flow between separators, ensuring equal flow paths and maintaining similar flow pressure to reaction cells, using a hot melt-type pressure-sensitive adhesive with greater compressibility than the gas diffusion layers and gaskets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the dummy cell uses a conventional configuration without membrane-electrode assembly, then the structure is simplified and manufacturing is easier, but the reaction gas flow pressure becomes lower than that of reaction cells, causing performance degradation

Engineering Contradiction:

Improvedummy cell structure simplificationVSAvoidreaction gas flow pressure

Core Design Contradiction:

Ease of manufactureVSStress or pressure

Solution Approach 1:

The patent applies local quality by selectively placing membrane-electrode assemblies only in specific dummy cells (first and second dummy cells) while omitting them from other dummy cells. This creates different flow resistance characteristics in different regions of the stack, allowing the first dummy cell to generate sufficient backpressure to balance differential pressure between reaction cells and dummy cells, while other dummy cells remain structurally simplified for ease of manufacture.

Inventive Principle:

Principle #3Local quality

2Device complexity

If the dummy cell has open flow paths on both separator sides, then the device complexity is reduced, but the flow rate of reaction gas to reaction cells decreases and water discharge becomes problematic

Engineering Contradiction:

Improvedummy cell flow path configurationVSAvoidreaction gas flow rate

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent segments the dummy cell flow paths by introducing a flow path blocking portion in the second dummy cell that blocks the reaction gas flow path between the second separator and the second gas diffusion layer. This divides the originally open flow path into restricted segments, ensuring that reaction gas is directed primarily to reaction cells while still maintaining structural simplicity in the dummy cell configuration.

Inventive Principle:

Principle #1Segmentation

3Stress or pressure

If the dummy cell restricts reaction gas flow paths, then the flow pressure increases to match reaction cells, but the device complexity increases

Engineering Contradiction:

Improvereaction gas flow pressureVSAvoiddummy cell structure

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of adding complex flow restriction structures to all dummy cells to increase pressure, the patent inverts the approach by using the presence of membrane-electrode assemblies in select dummy cells to naturally generate flow resistance and backpressure. This uses the 'normal' reaction cell structure in specific locations to achieve the pressure balancing function, rather than adding specialized restriction structures.

Inventive Principle:

Principle #13The other way round (Inversion)

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 minimizes reaction gas flow rate loss in the dummy cell, secures sufficient flow to reaction cells, and improves water dischargeability, enhancing overall fuel cell stack performance by maintaining balanced differential pressures.

Implementation Method 1

an airtight adhesive applied to a space between the dummy gas diffusion layers and the sealing gaskets between the pair of separators to prevent the reaction gas flown into one separator of the pair of separators from flowing to the other separator

Methodology Applied

Scientific EffectAdhesive: Adhesive

Implementation Method 2

The compressibility of the airtight adhesive is greater than those of the dummy gas diffusion layers and the sealing gaskets

Methodology Applied

Scientific EffectCompressibility: Compression

Data Source

PatentUS20240063404A1Dummy Cell for Fuel Cell and Fuel Cell Stack Including Same

Publication Date: 2024.02.22 HYUNDAI MOTOR CO LTD

AI summary

In an embodiment a dummy cell includes a pair of dummy gas diffusion layers laminated on each other, a pair of separators which are laminated with the pair of gas diffusion layers interposed therebetween, and in which sealing gaskets forming an airtight line are disposed in an outer region of a region where the dummy gas diffusion layers are disposed and an airtight adhesive arranged between the dummy gas diffusion layers and the sealing gaskets and between the pair of separators, the airtight adhesive configured to prevent a reaction gas flowing from one separator to another separator.