Nested Annular Metal-Air Cell Layout for Uniform Current Density

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Solution Overview

Problem

Existing metal-air cells face challenges in optimizing space management and arrangement of electrodes, leading to inefficiencies in current density and edge effects, particularly in rectangular or planar configurations.

Innovation Solution

The implementation of nested annular electrodes, where the fuel electrode is nested within the oxidant electrode, along with an optional oxygen evolution electrode, enhances space management and reduces edge effects, improving current density and C-rate capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rectangular or planar electrode configurations are used, then manufacturing is simpler, but space utilization is inefficient and edge effects increase

Engineering Contradiction:
Improveelectrode fabrication simplicityVSAvoidspace utilization efficiency
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent implements a nested annular configuration where the fuel electrode is positioned inside the oxidant electrode, creating a concentric arrangement. This nesting approach maximizes space utilization by eliminating wasted edge spaces and allowing both electrodes to be fully utilized for electrochemical reactions, directly resolving the contradiction between simple manufacturing and efficient space use.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from rectangular/planar geometries to annular (curved) electrode configurations. This curvature eliminates the edge effects inherent in flat electrodes and creates a more uniform current distribution across the electrode surfaces, improving both space utilization and electrochemical performance while maintaining manufacturing feasibility through rolling or bending processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If traditional planar electrode arrangements are used, then device structure is simpler, but current density distribution is non-uniform due to edge effects

Engineering Contradiction:
Improveelectrode arrangement structureVSAvoidcurrent density uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The annular configuration replaces planar surfaces with curved surfaces, eliminating edges where non-uniform current density typically occurs. The concentric arrangement ensures that all points on both electrode surfaces are at optimal distances from each other, creating uniform current distribution and improving manufacturing precision for electrochemical performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The nested configuration positions the fuel electrode concentrically within the oxidant electrode, ensuring uniform spacing and optimal reaction geometry throughout. This eliminates the edge effects of planar arrangements and creates consistent current density across the entire electrode surface area.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If nested annular electrodes are implemented, then space utilization and current density improve, but device complexity increases

Engineering Contradiction:
Improvespace utilization efficiencyVSAvoidelectrode configuration complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

While the annular configuration adds geometric complexity compared to flat electrodes, it can be manufactured using standard rolling or bending processes. The curved geometry provides significant benefits in space utilization and current density uniformity, making the increased complexity worthwhile and manageable through conventional fabrication techniques.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The nested arrangement, while more complex than planar stacking, creates a compact structure that maximizes the use of available cell volume. The concentric positioning of electrodes eliminates wasted space and improves electrochemical efficiency, justifying the increased structural complexity through superior performance.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 nested annular configuration optimizes space utilization, enhances current density, and improves the C-rate capabilities of metal-air cells, addressing inefficiencies in traditional electrode arrangements.

Implementation Method 1

a liquid ionically conductive medium, that is contained by the oxidant electrode, for conducting ions for supporting electrochemical reactions at the fuel electrode and the oxidant electrode

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

an oxidant electrode for absorbing gaseous oxidant and having one or more active materials for reducing the gaseous oxidant

Methodology Applied
Scientific EffectGas absorption: Absorption (physical)

Implementation Method 3

a fuel electrode for oxidizing a metal fuel

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

one or more active materials for reducing the gaseous oxidant

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3966887B1Nested annular metal-air cell and systems containing same
Publication Date: 2025.07.02 FORM ENERGY INC
  • EP3966887B1 patent drawingFigure 1A
  • EP3966887B1 patent drawingFigure 1B~1C
  • EP3966887B1 patent drawingFigure 2A

AI summary

Electrochemical metal-air cells having nested electrodes provided in an annular or cylindrical configuration, including systems that contain such cells in a sealed container. Each cell may include an oxidant electrode (air cathode) and a fuel electrode (anode), both configured in annular form. A series of permeable bodies, screens, or current collectors may be provided as part of the fuel electrode. An annular oxygen evolution electrode may also be provided in the cells. In some cases, the fuel electrode is nested within the oxidant electrode, or vice versa. Optionally, a second oxidant electrode may be included in the cells. Ionically conductive medium or electrolyte may be contained in the cell. Each cell may have its own cell housing. Optionally, an air space or pocket may be formed in a cell via an oxidant electrode. The sealed container may contain the cells such that they are surrounded by air or an electrolyte.