Flow-By Electrode Surface Structure for Low-Loss Redox Flow Batteries

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Solution Overview

Problem

Redox flow batteries face inefficiencies due to high voltage losses, ohmic losses, and transport limitations, particularly with flow-through electrodes that require high pressure and result in inhomogeneous current distribution and rapid degradation, limiting their performance and scalability.

Innovation Solution

The introduction of a flow-by electrode unit with an open flux surface structure that promotes optimized electrolyte flow, reducing laminar boundary layers and increasing the electrochemically active surface area, allowing higher flow velocities and reducing flow resistance, thereby enhancing mass transport and cell performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If flow-through electrodes are used to increase electrochemical reaction surface area, then mass transport is enhanced, but voltage losses and ohmic losses increase due to high pressure requirements

Engineering Contradiction:
Improvemass transport efficiencyVSAvoidvoltage losses and ohmic losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent inverts the conventional flow-through electrode design by using flow-by electrodes where electrolyte flows along the electrode surface rather than through porous structures. This reversal eliminates the need for high pressure to drive flow through pores, thereby reducing ohmic losses and voltage losses while maintaining effective mass transport through enhanced convective flow along the electrode surface.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent eliminates the use of porous electrode materials that cause high resistance and pressure requirements. By using non-porous flow-by electrodes with electrolyte flowing along the surface, the invention reduces electrical resistance and eliminates the need for high pressure pumping, thereby reducing energy losses while maintaining electrochemical reaction efficiency.

Inventive Principle:
Principle #31Porous materials

2Productivity

If flow-through electrodes operate at high pressure to maintain flow velocity, then mass transport is improved, but electrode degradation accelerates

Engineering Contradiction:
Improvemass transport rateVSAvoidelectrode durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent inverts the flow configuration from flow-through to flow-by, where electrolyte flows along the electrode surface rather than through porous structures under high pressure. This eliminates the mechanical stress and high pressure that cause electrode degradation, thereby extending electrode lifespan while maintaining effective mass transport through convective flow.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If conventional flow distribution is used in redox flow batteries, then system simplicity is maintained, but hydraulic losses increase due to inhomogeneous current distribution

Engineering Contradiction:
Improvesystem complexityVSAvoidhydraulic losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating specific flow channel geometries and electrode surface structures that optimize local flow distribution. This ensures homogeneous current distribution across the electrode surface by controlling local flow characteristics, thereby reducing hydraulic losses while maintaining overall system simplicity through straightforward flow-by configuration.

Inventive Principle:
Principle #3Local quality

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 solution improves the energy efficiency and scalability of redox flow batteries by reducing hydraulic losses, extending cell length, and maintaining high flow velocities, while minimizing electrode degradation and operational costs.

Implementation Method 1

promotes optimized electrolyte flow, reducing laminar boundary layers and increasing the electrochemically active surface area, allowing higher flow velocities and reducing flow resistance

Methodology Applied
Scientific EffectLaminar boundary layer reduction: Boundary Layer

Implementation Method 2

enhancing mass transport and cell performance

Methodology Applied
Scientific EffectMass transport enhancement: Convection

Implementation Method 3

allowing higher flow velocities and reducing flow resistance

Methodology Applied
Scientific EffectFlow resistance reduction: Drag

Implementation Method 4

Redox flow batteries (RFBs) are electrochemical storage devices for storing electrical energy in the form of chemical energy contained in molecules and/or ions, which form reversible redox couples

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP3580802B1Flow-by electrode unit and use thereof, redox flow battery system and use thereof, method of manufacturing a flow-by electrode unit, method of operating a redox flow battery system
Publication Date: 2023.08.30 CMBLU ENERGY AG
  • EP3580802B1 patent drawingFigure 1
  • EP3580802B1 patent drawingFigure 2a~2b
  • EP3580802B1 patent drawingFigure 3~5

AI summary

A flow-by electrode unit is provided, in particular for a redox flow battery, including a flow-by electrode which includes a substrate and has at least one open flux surface structure. Moreover, a use of the flow-by electrode unit, a method of manufacturing a flow-by electrode unit, a redox flow battery system and a use thereof, and a method of operating a redox flow battery system is described.