Redox Flow Battery Spacer for Frame Deformation Control

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Solution Overview

Problem

Redox flow batteries with elastomeric stack frames face issues with maintaining tightness due to deformation caused by clamping pressure, leading to potential electrolyte leakage and corrosion, especially at the current collector, which compromises the battery's efficiency and longevity.

Innovation Solution

The use of spacers that cover at least 75% to 90% of the stack frame side surfaces, made from materials like PVC, PE, or PTFE, with a thermal expansion coefficient matching the stack frame, to prevent deformation and ensure even support, thereby maintaining the seal and alignment of the stack frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If clamping means press the end plates together to secure the cell stack, then the structural stability is improved, but the elastomeric stack frames deform and sealing effectiveness deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidsealing effectiveness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

A spacer is introduced as an intermediary element between the end plates and elastomeric stack frames. The spacer distributes the clamping force more uniformly across the stack frames, preventing localized deformation while maintaining overall structural stability. This mediator component resolves the contradiction by allowing compression without excessive deformation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spacer modifies the pressure distribution parameters by changing the contact area and force density between end plates and stack frames. By adjusting the spacer geometry and material properties, the clamping force is optimized to maintain sealing pressure without causing frame deformation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If spacers are added to prevent frame deformation, then sealing effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spacer is designed as a thin, flexible component that can deform slightly to accommodate manufacturing tolerances and assembly variations. This simple geometric form minimizes the added complexity while effectively distributing clamping forces to prevent frame deformation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The spacer is made from materials with thermal expansion coefficients matched to the stack frames, ensuring uniform behavior under temperature changes. This homogeneity in material properties simplifies the overall system response to environmental conditions without requiring complex compensation mechanisms.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If elastomeric materials are used for stack frames to improve sealing, then sealing effectiveness is improved, but resistance to deformation under clamping pressure deteriorates

Engineering Contradiction:
Improvesealing effectivenessVSAvoidresistance to deformation
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The system combines elastomeric stack frames with rigid spacer components to create a composite structure. The elastomer provides sealing compliance while the rigid spacer provides dimensional stability and resistance to deformation under clamping loads, resolving the contradiction between flexibility and strength.

Inventive Principle:
Principle #40Composite 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 solution effectively prevents unwanted deformation of the elastomeric stack frames, enhancing both internal and external sealing, reducing the risk of electrolyte leakage and corrosion, and ensuring consistent performance across temperature fluctuations.

Implementation Method 1

frames made of elastic plastics (elastomers) are also known... elastomers are dimensionally stable but elastically deformable

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

clamping means are provided that press the first end plate and the second end plate together... pressing the end faces of the individual stack frames together

Methodology Applied
Scientific EffectPressure distribution: Pressure Increase

Implementation Method 3

at least one spacer is arranged between the first end plate and the second end plate to set a distance... in flush contact with at least 75%, preferably 90%, of the stack side surfaces

Methodology Applied
Scientific EffectMechanical contact and friction: Friction

Implementation Method 4

Lubrication of the spacers can be advantageous for assembling the cell stack, enabling the stack frames to slide into the desired position

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 5

the coefficient of thermal expansion of the spacers is matched to the stacking frames... the stack frame and spacers expand or contract equally in response to temperature changes

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3420609B1Spacer for a cell stack
Publication Date: 2019.12.25 ENEROX GMBH
  • EP3420609B1 patent drawingFigure 1~2
  • EP3420609B1 patent drawingFigure 3
  • EP3420609B1 patent drawingFigure 4~5

AI summary

In order to ensure the sealing tightness of redox flow batteries (1) having elastomer stack frames (3) that are pressed together, a cell stack (5) is disclosed that includes at least one spacer (81) which lies flush on at least 75%, preferably at least 90%, of the lateral faces (51) of at least one side (50) of the stack.