Fuel Cell Separator Structure for Gas Transfer and Water Discharge

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Solution Overview

Problem

Conventional fuel cell separators face issues with inefficient reaction gas transfer, water discharge, contact resistance, and performance instability due to unclear distinction between gas and water transfer passages, leading to reduced efficiency and instability in high output regions.

Innovation Solution

A separator design featuring sequentially arranged convex and concave portions with inclined surfaces and non-coaxial openings to enhance gas transfer, water discharge, and contact area, optimizing convection/diffusion mixed flow and moisture management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional separators with two-dimensional channels or three-dimensional solid shapes are used, then the structure is simple to manufacture, but the water discharge performance deteriorates under various operation conditions

Engineering Contradiction:
Improvestructural simplicityVSAvoidwater discharge performance
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The separator surface is segmented into convex portions and concave portions with distinct functions. Convex portions provide contact areas with the gas diffusion layer, while concave portions form water collection channels. This segmentation allows simultaneous optimization of gas transfer, water discharge, and structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional two-dimensional channels to a three-dimensional surface structure with convex and concave portions. This dimensional enhancement creates dedicated water collection regions that improve water discharge performance while maintaining manufacturing simplicity through stamping or molding processes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If metal mesh or expanded metal separators are used, then the contact area with gas diffusion layer is increased, but the transfer passages become unclear and condensed water occlusion occurs

Engineering Contradiction:
Improvecontact areaVSAvoidperformance stability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

Different regions of the separator are assigned different functions: convex portions provide contact areas with the gas diffusion layer for electrical connection, while concave portions serve as water collection channels. This local differentiation ensures clear passage distinction, prevents water occlusion in microchannels, and maintains performance stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The separator is segmented into functional zones with convex portions for gas transfer and electrical contact, and concave portions for water collection. This segmentation creates clearly defined transfer passages that prevent condensed water occlusion while maintaining adequate contact area.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If conventional separators with intersecting three-dimensional solid shapes are used, then the gas distribution is improved, but the reaction gas transfer rate decreases due to mass transfer resistance

Engineering Contradiction:
Improvegas distribution uniformityVSAvoidreaction gas transfer rate
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The invention extracts the water collection function from the gas distribution structure by creating separate concave portions dedicated to water discharge. This separation eliminates mass transfer resistance caused by water accumulation in gas passages, thereby improving reaction gas transfer rate while maintaining uniform gas distribution through the convex contact areas.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If separators without distinguished transfer passages are used, then the device complexity is reduced, but the reaction gas supply efficiency decreases due to condensed water occlusion

Engineering Contradiction:
Improvepassage structure complexityVSAvoidreaction gas supply efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The separator is segmented into convex portions for gas transfer and concave portions for water collection. This segmentation creates naturally defined transfer passages without complex internal structures, preventing condensed water occlusion while maintaining low device complexity suitable for stamping or molding manufacturing.

Inventive Principle:
Principle #1Segmentation

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 separator improves reaction gas transfer rates, reduces contact resistance, and efficiently discharges condensed water, stabilizing fuel cell performance by ensuring efficient gas and liquid flow distribution and preventing water accumulation.

Implementation Method 1

improving heat and mass transfer characteristics by a convection/diffusion mixed flow

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

improving heat and mass transfer characteristics by a convection/diffusion mixed flow

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

a separator capable of efficiently discharging condensed water

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3490045B1Separation plate, and fuel cell stack comprising same
Publication Date: 2023.08.30 LG CHEM LTD
  • EP3490045B1 patent drawingFigure 1~3
  • EP3490045B1 patent drawingFigure 4
  • EP3490045B1 patent drawingFigure 5

AI summary

The present invention relates to a separator and a fuel cell stack comprising the same, and according to one aspect of the present invention, there is provided a separator comprising a plurality of convex portions and a plurality of concave portions which are sequentially provided along a first direction, wherein in the convex portions, first openings are each provided on top surfaces at predetermined intervals along a second direction orthogonal to the first direction and the first openings of two adjacent convex portions are each provided so as not to be positioned coaxially based on a virtual first line parallel to the first direction.