Fuel Cell Flow Field Plate Boundary Sealing for Reactant Bypass

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Solution Overview

Problem

In fuel cell assemblies, reactant fluids tend to bypass the flow field at the edges due to flow resistance, and existing bypass stopping elements fail to provide reliable sealing due to stacking imperfections, leading to leakage.

Innovation Solution

The introduction of bypass stopping elements with a pointed portion that compresses the multilayer membrane electrode assembly and gas diffusion layers, ensuring effective sealing even with slight misalignments, combined with a bead seal for enhanced sealing properties and a design that allows for manufacturing flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If bypass stopping elements are provided in the boundary area, then reactant bypassing is avoided, but sealing reliability deteriorates due to stacking imperfections

Engineering Contradiction:

Improvereactant bypass lossVSAvoidsealing reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The bypass stopping element features a pointed portion with a locally reduced cross-sectional area in the boundary area between the flow field and bead seal. This localized geometric modification creates high contact pressure at specific points to ensure reliable sealing against stacking imperfections, while maintaining the overall structural integrity of the component.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cross-sectional area of the bypass stopping element is varied along its length, with a minimum cross-sectional area at the pointed portion that contacts the bead seal. This parameter change enables the element to generate sufficient contact pressure for reliable sealing while accommodating variations in stacking height due to manufacturing tolerances.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the bypass stopping element has a larger cross-sectional area, then sealing contact is improved, but reactant bypass increases due to insufficient compression

Engineering Contradiction:

Improvesealing contactVSAvoidreactant bypass

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The bypass stopping element features a pointed portion with a locally reduced cross-sectional area at the sealing surface. This localized geometric modification creates high contact pressure at specific points to ensure reliable sealing, while the overall element geometry maintains sufficient structural support.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the flow field structure is made more prominent for better reactant distribution, then distribution efficiency is improved, but flow resistance increases causing more bypass

Engineering Contradiction:

Improvereactant distribution efficiencyVSAvoidreactant bypass loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The flow field plate is segmented into a flow field structure with channels for reactant distribution and a boundary area with bypass stopping elements. This segmentation allows the flow field structure to be optimized for reactant distribution while the bypass stopping elements in the boundary area prevent edge bypass, addressing both requirements simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bypass stopping elements act as intermediary structures positioned in the boundary area between the flow field and bead seal. These elements mediate between the flow field structure and the sealing system, preventing reactant bypass while allowing the flow field structure to maintain its design for optimal reactant distribution.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively prevents reactant bypassing, maintaining high sealing properties and electrical efficiency while reducing manufacturing complexity and costs, particularly for hydrogen fuel cells where small molecule reactants pose challenges.

Implementation Method 1

the at least one bypass stopping element has a pointed portion which is adapted to compress the multilayer membrane electrode assembly

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS20230420701A1Fuel cell assembly

Publication Date: 2023.12.28 POWERCELL SWEDEN AB

AI summary

A fuel cell assembly includes at least a first flow field plate and a second flow field plate sandwiching a multilayer membrane electrode assembly, wherein the multilayer membrane electrode assembly comprises at least a 3-layer membrane electrode assembly including a first electrode facing the first flow field plate, a second electrode facing the second flow field plate and a membrane separating the electrodes, wherein each flow field plate has a flow field structure protruding from a base level of the flow field plate for distributing reactant over the respective electrode, and wherein further at least one sealing element is arranged between the first and the second flow field plate, which is adapted to prevent leakage of the reactants to an environment, wherein in a boundary area between the flow field structure and the sealing element of at least one of the flow field plates at least one bypass stopping element is arranged for avoiding the reactant bypassing the flow field structure, wherein the bypass stopping element protrudes from the respective base level of the flow field plate, wherein the at least one bypass stopping element has a pointed portion, which is adapted to compress the multilayer membrane electrode assembly, as well as a flow field plate for such a fuel cell assembly.