Redox Flow Battery Frame Body Surface Roughness

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Solution Overview

Problem

Cell frames in redox flow batteries experience displacement due to vibration or internal pressure, leading to electrolyte leakage when surfaces are excessively smooth, while excessively rough surfaces create large gaps that also result in leakage.

Innovation Solution

The frame body and cell frame feature frame-facing surfaces with a surface roughness of 0.03 µm to 3.2 µm, and sealing grooves with matching roughness to prevent displacement and ensure proper sealing, using a loop-shaped sealing member to enhance friction and adherence, thereby reducing electrolyte leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the frame-facing surface is made excessively smooth, then the sealing performance is improved, but the cell frames become displaced due to vibration or internal pressure

Engineering Contradiction:
Improvesealing performanceVSAvoidposition stability of cell frames
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by optimizing the surface roughness of the frame-facing surface within a specific range (Ra 0.03-3.2 µm). This parameter optimization balances two opposing requirements: sufficient smoothness for sealing performance and sufficient roughness for friction-based position stability during vibration and pressure conditions.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the frame-facing surface is made excessively rough, then the position stability of cell frames is improved, but large gaps are formed between adjacent cell frames

Engineering Contradiction:
Improveposition stability of cell framesVSAvoidsealing performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent resolves this contradiction by establishing an upper bound for the surface roughness parameter (Ra ≤ 3.2 µm). This ensures that while sufficient friction is maintained for position stability, the surface does not become so rough as to create large gaps that would compromise sealing performance.

Inventive Principle:
Principle #35Parameter changes

3Force

If the surface roughness is increased to prevent displacement, then the friction between adjacent cell frames is improved, but the manufacturing precision requirements become more stringent

Engineering Contradiction:
Improvefriction force between cell framesVSAvoidsurface roughness control precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent balances friction force requirements with manufacturing feasibility by specifying a surface roughness range (Ra 0.03-3.2 µm) that provides sufficient friction while remaining achievable through conventional manufacturing processes. This range avoids extreme values that would be difficult to control precisely during manufacturing.

Inventive Principle:
Principle #35Parameter changes

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 effectively suppresses electrolyte leakage during transportation and operation by maintaining appropriate friction between adjacent cell frames and ensuring the loop-shaped sealing member remains in place, preventing gaps and enhancing sealing performance.

Implementation Method 1

the frame-facing surfaces of the one surface and the other surface of the frame body have a surface roughness Ra of 0.03 µm or more and 3.2 µm or less

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

using a loop-shaped sealing member to enhance friction and adherence, thereby reducing electrolyte leakage

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3525276B1Frame body, cell frame, cell stack, and redox flow battery
Publication Date: 2020.07.08 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3525276B1 patent drawingFigure 1
  • EP3525276B1 patent drawingFigure 2
  • EP3525276B1 patent drawingFigure 3

AI summary

A frame body that is a part of a flat cell frame for a cell stack of a redox flow battery, and that supports, on an outer peripheral side of a bipolar plate of the cell frame, the bipolar plate, the frame body including a frame-facing surface that is to face, when a plurality of the cell frames are stacked, a frame body of another cell frame that is adjacent to the cell frame in a stacking direction, wherein the frame-facing surface has a surface roughness Ra of 0.03 µm or more and 3.2 µm or less.