Bipolar Plate Ridge Roughness for Electrode Positioning

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Solution Overview

Problem

Existing bipolar plates in redox flow batteries lack features to prevent electrode positional misalignment during assembly and ensure effective electrolyte diffusion, leading to potential inefficiencies in battery reaction.

Innovation Solution

The bipolar plate design incorporates groove sections and ridge sections with uneven portions, such as rough surfaces, steps, or inclined surfaces, to prevent electrode sliding and enhance electrolyte diffusion by creating turbulent flow, thereby improving electrode positioning and reactivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a bipolar plate with groove sections is used to adjust electrolyte flow, then pressure loss of electrolyte decreases, but electrode positional misalignment occurs during assembly

Engineering Contradiction:
Improvepressure lossVSAvoidelectrode positioning
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The bipolar plate incorporates ridge sections with different surface properties (roughness, height variations) at specific locations to provide localized electrode positioning functions while maintaining smooth groove sections for optimized electrolyte flow, thus resolving the conflict between flow efficiency and positioning precision

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Ridge sections act as intermediary structures between the groove sections, providing both structural support for electrode positioning and flow guidance functions, thereby mediating between the conflicting requirements of minimal pressure loss and precise electrode alignment

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If ridge sections are added to prevent electrode sliding, then electrode positioning improves, but device complexity increases

Engineering Contradiction:
Improveelectrode positioningVSAvoidbipolar plate structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The ridge sections serve multiple functions simultaneously: they provide electrode positioning, prevent sliding, guide electrolyte flow, and maintain structural integrity, thereby reducing the need for separate components and minimizing overall device complexity while achieving precise electrode positioning

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The design effectively prevents electrode misalignment and enhances electrolyte diffusion, leading to improved battery reactivity and reduced unreacted electrolyte discharge.

Implementation Method 1

the ridge section includes an uneven portion configured to suppress sliding of the positive electrode or the negative electrode... the uneven portion includes a rough surface provided on at least a part of a surface of the ridge section

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the electrolyte flows so as to traverse between the adjacent groove sections over a section (hereinafter referred to as a 'ridge section') located between the groove sections, and the electrolyte conducts a battery reaction on the electrode facing the ridge section

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP3346537B1Bipolar plate, cell frame and cell stack, and redox flow battery
Publication Date: 2021.06.02 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3346537B1 patent drawingFigure 1
  • EP3346537B1 patent drawingFigure 2
  • EP3346537B1 patent drawingFigure 3

AI summary

A bipolar plate for a battery has a surface on which a positive electrode is to be disposed and another surface on which a negative electrode is to be disposed. At least one of the surfaces of the bipolar plate is provided with a plurality of groove sections through which an electrolyte flows and a ridge section located between the groove sections that are adjacent to each other. The groove sections include an introduction groove section and a discharge groove section that are not in communication with each other. The ridge section includes an uneven portion configured to suppress sliding of the positive electrode or the negative electrode in a direction in which the adjacent groove sections are arranged in parallel. The uneven portion includes a rough surface provided on at least a part of a surface of the ridge section. The rough surface has a surface roughness of 0.1 µm or more and 10 µm or less in terms of arithmetical mean roughness Ra.