Slotted Felt Flow Structure for Redox Flow Cell Wetting

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Solution Overview

Problem

Existing redox flow converters face challenges in balancing low-resistance electrolyte flow with sufficient electrolyte mixing and wetting of electrode plates, which affects the efficiency of electrochemical reactions.

Innovation Solution

The use of slotted felt on electrode plates with geometrically defined slots aligned in the flow direction, allowing for efficient electrolyte flow and mixing, while minimizing material displacement and shunt currents, combined with graphite-based electrode plates for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If felt material is used on electrode plates, then electrolyte conduction is enabled, but shunt currents occur due to material displacement

Engineering Contradiction:
Improveelectrolyte conductionVSAvoidshunt currents
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The felt material is provided with slot-shaped openings that create localized flow channels where electrolyte conduction is enhanced. This local structuring ensures that current flows primarily through the intended electrochemical pathways rather than being dispersed through material displacement, thereby reducing shunt currents while maintaining effective electrolyte conduction.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If simple felt structure is used, then manufacturing is simple, but fluid dynamics performance is insufficient

Engineering Contradiction:
Improvefelt structure manufacturingVSAvoidfluid dynamics performance
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The felt is manufactured with defined slot-shaped openings that can be created through standard manufacturing processes such as laser cutting or mechanical punching. This approach maintains relative manufacturing simplicity while dramatically improving fluid dynamics performance by creating controlled flow channels that enhance electrolyte distribution, mixing, and contact with the electrode surface.

Inventive Principle:
Principle #31Porous materials

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 configuration achieves high area-related maximum currents and high volume-related stack power, with efficiency up to 98% for electricity generation or electrolyte regeneration, and reduces shunt losses through optimized fluid dynamics and structural stability.

Implementation Method 1

a slotted felt 6 resting on the electrode plate 3... geometrically defined openings having a slot-like shape 8 in the felt 6

Methodology Applied
Scientific EffectFluid flow through porous material: Porosity

Implementation Method 2

Redox flow converters are electrochemical energy converters, commonly referred to as flow batteries, designed to convert chemically bound energy into electrical energy or vice versa

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 3

The half-cells comprise a current collector and an electrode element arranged in an interior space of the respective half-cell through which an electrolyte can flow

Methodology Applied
Scientific EffectIon conduction through membrane: Semipermeable Membrane

Data Source

PatentEP4496046A1Redox flow converter
Publication Date: 2025.01.22 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4496046A1 patent drawingFigure 1~2
  • EP4496046A1 patent drawingFigure 3~4
  • EP4496046A1 patent drawingFigure 5~7

AI summary

A redox flow converter (1) comprises a plurality of redox flow cells (2), which include electrode plates (3) and fluid-conducting structures. The fluid-conducting structures are formed by a felt (6) with slots (8) resting on the electrode plate (3).