Flexible Mesh Cathode for Modular Electrolyser Current Distribution

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Solution Overview

Problem

Industrial electrolysis processes face challenges in maintaining the planarity and parallelism of cathodes and anodes, leading to inhomogeneous electric current distribution and reduced separator lifetime due to misalignment and compression issues, which increases energy consumption and maintenance complexity.

Innovation Solution

The implementation of a single-cell design with a cathode-anode zero-gap configuration using a flexible planar mesh cathode coupled with an elastic element ensures uniform current distribution and reduced mechanical stress on separators, allowing for easier assembly and maintenance while minimizing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional bipolar element design with cathode-anode gap is used, then assembly is simpler, but current distribution becomes inhomogeneous and separator lifetime decreases

Engineering Contradiction:
Improveassembly simplicityVSAvoidcurrent distribution uniformity and separator lifetime
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The cathode is designed as a flexible planar mesh that can conform to the separator surface, eliminating the need for precise parallelism between cathode and anode. This flexibility allows the cathode to maintain uniform contact with the separator even when the rigid anode structure has slight deviations, thereby achieving homogeneous current distribution without complex alignment procedures during assembly.

Inventive Principle:
Principle #30Flexible shells and thin films

2Manufacturing precision

If precise alignment and compression adjustments are implemented, then current distribution improves, but device complexity and maintenance difficulty increase

Engineering Contradiction:
Improvecathode-anode parallelismVSAvoidalignment and compression adjustment mechanisms
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The flexible mesh cathode automatically adapts to the separator surface geometry through its inherent flexibility, eliminating the need for external alignment mechanisms or compression adjustments. The system self-regulates to achieve uniform current distribution without requiring complex control systems or precise manufacturing tolerances for the supporting structures.

Inventive Principle:
Principle #25Self-service

3Reliability

If external tie-rods or hydraulic jacks are used for compression, then tightness seal is ensured, but separator damage risk increases due to misalignment and sliding

Engineering Contradiction:
Improvetightness sealVSAvoidseparator damage from misalignment and compression
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The flexible mesh cathode acts as a buffer between the compression force from external tie-rods or hydraulic jacks and the separator. When compression is applied, the flexible mesh deforms to accommodate slight misalignments and prevents direct transmission of concentrated stresses to the separator, thereby reducing the risk of separator damage while maintaining the required tightness seal.

Inventive Principle:
Principle #30Flexible shells and thin films

4Strength

If cathode is made rigid for structural stability, then mechanical strength is maintained, but adaptability to separator surface variations decreases

Engineering Contradiction:
Improvecathode structural stabilityVSAvoidcathode conformity to separator surface
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The cathode is constructed as a flexible planar mesh with sufficient mechanical strength to withstand operational conditions while maintaining the ability to conform to the separator surface. The mesh structure provides both the required structural stability and the flexibility to adapt to surface variations, combining the benefits of rigid and flexible designs.

Inventive Principle:
Principle #30Flexible shells and thin films

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 design achieves a homogeneous electric current distribution, reduces energy consumption by approximately 170 kWh per tonne of product, and extends the lifespan of separators by eliminating the need for precise alignment and compression adjustments.

Implementation Method 1

an elastic element 35, for instance consisting of the juxtaposition of two or more corrugated conductive metal cloths or of a mat formed by interpenetrated coils obtained from one or more metal wires

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Industrial electrolysis processes, for instance water electrolysis for hydrogen and oxygen production and electrolysis of alkali brine, in particular of sodium chloride brine, directed to the production of chlorine, caustic soda and hydrogen

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Data Source

PatentEP2356266B8Elementary cell and relevant modular electrolyser for electrolytic processes
Publication Date: 2015.08.26 THYSSENKRUPP UHDE CHLORINE ENGINEERS ITAL S R

AI summary

An electrolysis cell provided with a separator, suitable for chlor-alkali electrolysis, has a planar flexible cathode kept in contact with the separator by an elastic conductive element pressed by a current distributor and an anode consisting of a punched sheet or mesh supporting the separator. The cell is suitable for being individually pre-assembled and used as elementary unit of a modular arrangement to form an electrolyser whose terminal cells only are connected to the electric power supply; the electrical continuity between adjacent cells is assured by conductive contact strips secured to the external anodic walls of the shells delimiting each cell. The stiffness of the cathode current distributor and of the anodic structure and the elasticity of the conductive element cooperate in maintaining a uniform cathode to separator contact with a homogeneous pressure distribution meanwhile ensuring a suitable mechanical load on the contact strips.