Fuel Cell Stack Gas Distribution Layer Recesses

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Solution Overview

Problem

Fuel cells with non-profiled bipolar plates and porous flow bodies face suboptimal volumetric power density, sluggish dynamic behavior, increased pressure loss, and uneven reactant distribution compared to conventional profiled bipolar plates.

Innovation Solution

A fuel cell stack design featuring non-profiled bipolar plates with a gas distribution layer comprising a porous flow body and recesses in the active region, which reduces design height and improves mass transport by providing diffuse and discrete flow channels for uniform gas distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If porous flow bodies are used in non-profiled bipolar plates, then the volume of the fuel cell is reduced, but the volumetric power density is not optimal

Engineering Contradiction:

Improvefuel cell volumeVSAvoidvolumetric power density

Core Design Contradiction:

Volume of moving objectVSPower

Solution Approach 1:

The gas distribution layer is segmented into multiple functional zones: porous flow bodies for diffuse distribution and recesses with flow channels for discrete high-velocity flow paths. This segmentation allows the system to achieve both compact volume and high volumetric power density by combining the advantages of different flow distribution mechanisms within the same structure.

Inventive Principle:

Principle #1Segmentation

2Length of stationary object

If porous flow bodies are used instead of conventional flow channels, then the design height is reduced, but the dynamic behavior becomes sluggish

Engineering Contradiction:

Improvedesign heightVSAvoiddynamic behavior

Core Design Contradiction:

Length of stationary objectVSSpeed

Solution Approach 1:

Different regions of the gas distribution layer are assigned different flow characteristics: porous flow bodies provide uniform diffuse flow in most areas, while recesses with flow channels provide high-velocity discrete flow paths in specific locations. This local differentiation enables the system to achieve low design height while maintaining fast dynamic response where needed.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If porous flow bodies are used, then the pressure loss increases, but the reactant distribution becomes more uniform

Engineering Contradiction:

Improvereactant distribution uniformityVSAvoidpressure loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The invention merges two flow distribution mechanisms: porous flow bodies that provide uniform diffuse distribution and recesses with flow channels that provide low-resistance discrete flow paths. The combination allows reactants to be distributed uniformly across the membrane electrode assembly while maintaining lower overall pressure loss through the high-velocity channels.

Inventive Principle:

Principle #5Merging (Combining)

4Device complexity

If non-profiled bipolar plates with porous flow bodies are used, then the manufacturing complexity is reduced, but the water discharge performance degrades

Engineering Contradiction:

Improvebipolar plate structureVSAvoidwater discharge performance

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The recesses with flow channels act as intermediary structures that facilitate water discharge. While the porous flow bodies provide uniform gas distribution, the recesses serve as dedicated pathways for water removal, mediating between the diffuse flow distribution and the need for efficient water discharge, thus improving overall performance without complicating the basic non-profiled plate design.

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 design enhances volumetric power density, reduces pressure loss, and improves reactant distribution, leading to increased fuel cell efficiency, longer lifespan, and more robust performance.

Implementation Method 1

The flow body has connected pores which form diffuse flow channels for distributing the reactant gases

Methodology Applied

Scientific EffectDiffuse flow: Diffusion

Implementation Method 2

the flow body having recesses in the active region... improved mass transport by providing diffuse and discrete flow channels

Methodology Applied

Scientific EffectPressure gradient-driven flow: Pressure Gradient

Data Source

PatentUS10615429B2Fuel cell and fuel cell stack

Publication Date: 2020.04.07 AUDI AG

AI summary

The invention relates to a fuel cell stack (1), comprising: —bipolar plates (10), each having an active region (13a), wherein a surface of the bipolar plate is formed non-profiled at least in the active region (13a), —a membrane electrode assembly (20), arranged between two bipolar plates (10), and—a gas distribution layer (30) arranged between the membrane electrode assembly (20) and at least one of the bipolar plates (10), wherein the gas distribution layer (30) comprises a porous flow body (31). It is provided that the gas distribution layer (30) includes recesses (32) in the active region (13a).