Removable Air Electrode Cathode Compartment for Rechargeable Metal-Air Batteries

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Solution Overview

Problem

Metal-air batteries face instability and reduced lifespan during the charging phase due to the fragile porous structure of the air electrode, which is not designed for reverse oxidation, leading to mechanical damage and catalyst instability, limiting their commercial development as electrically rechargeable accumulators.

Innovation Solution

A cathode compartment is designed to house the air electrode in a plate form, allowing for easy extraction and replacement, with a liquid-tight structure, mechanical reinforcement, and compression features to manage the metal electrode, enabling continued use of the battery even when the air electrode reaches the end of its life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the air electrode uses a porous structure to provide large reaction surface area for oxygen reduction, then the current density and energy efficiency are improved, but the mechanical strength is reduced and the electrode becomes fragile during charging

Engineering Contradiction:
Improvecurrent densityVSAvoidmechanical strength
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The air electrode is segmented into multiple layers with different functions: a porous layer for high surface area reactions and a reinforced layer for mechanical strength. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air electrode uses composite materials combining porous carbon materials for electrochemical activity with reinforcing materials for mechanical strength. This composite structure maintains high current density while preventing electrode fragmentation during charging cycles.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the air electrode is designed for optimal oxygen reduction reaction, then the discharge performance is improved, but the stability during charging phase deteriorates due to mechanical destruction by oxygen gas release

Engineering Contradiction:
Improvedischarge performanceVSAvoidcharging stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The electrode structure incorporates beforehand cushioning elements and reinforced frameworks that prevent mechanical destruction before it occurs. These preventive structures absorb the stress of oxygen gas release during charging, preventing electrode fragmentation and maintaining reliability throughout the battery lifecycle.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If the catalyst is added to improve oxygen reduction reaction efficiency, then the energy efficiency is improved, but the catalyst stability at high potentials deteriorates leading to carbon corrosion

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcatalyst stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The catalyst system uses parameter changes by selecting catalyst materials and configurations that maintain high activity at lower potentials while being stable at the higher potentials required for oxygen evolution during charging. This optimizes the energy efficiency during discharge while ensuring catalyst stability during charging cycles.

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 solution extends the lifespan of the air electrode, allowing it to be replaced independently, thus prolonging the overall battery life and enabling continued use of the metal electrode, addressing the limitations of existing metal-air batteries.

Implementation Method 1

O 2 + 2·H 2 O + 4·e - positive electrode (air electrode)

Methodology Applied
Scientific EffectOxygen reduction reaction: Redox Reactions

Implementation Method 2

An air electrode is a porous solid structure in contact with the liquid electrolyte, which is usually an alkaline solution

Methodology Applied
Scientific EffectPorous structure: Porosity

Implementation Method 3

4·OH - positive electrode (air electrode)

Methodology Applied
Scientific EffectOxygen evolution reaction: Redox Reactions

Data Source

PatentEP3072175B2Battery having removable air electrode
Publication Date: 2022.01.26 ELECTRICITE DE FRANCE
  • EP3072175B2 patent drawingFigure 1~4
  • EP3072175B2 patent drawingFigure 5~7
  • EP3072175B2 patent drawingFigure 8~9

AI summary

The present invention relates to a rechargeable battery (1) including a casing (11) containing therein: an air electrode (22); a negative electrode (3); and an electrolyte (4), in which the air electrode (22) can be taken out of the casing. The rechargeable battery also relates to a cathode compartment (2) for an air electrode battery. Said compartment includes an air electrode and is insertable into a casing of the battery without being part of the casing. Said compartment is removably movable.