Wound Metal-Air Battery Cathode for Flexible High Capacity
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Solution Overview
Problem
Metal-air batteries with binder-free cathodes are brittle and lack flexibility, limiting their form and handling as a co-continuous body, which hinders capacity increase and environmental sustainability.
Innovation Solution
A metal-air battery with a wound structure using a cathode formed from a co-continuous body of integrated nanostructures, a metal anode, a liquid-absorbing separator, and a metal current collector, where the components are superimposed and wound in a specific order to enhance capacity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a binder-free cathode is used to reduce environmental impact and cost, then the battery becomes more environmentally friendly and cheaper, but the cathode becomes brittle and lacks flexibility, limiting the battery form and handling
Solution Approach 1:
The patent uses a composite structure combining carbon nanotubes (conductive phase) and binder-free cathode material (active phase). The carbon nanotubes form a flexible three-dimensional network that provides both structural integrity and flexibility, while the cathode material particles are dispersed within this network. This composite approach allows the cathode to maintain flexibility and mechanical strength without requiring traditional binders, thus resolving the contradiction between environmental friendliness and mechanical performance.
Solution Approach 2:
The patent creates local quality differentiation within the cathode structure by having conductive carbon nanotubes distributed throughout the cathode material. The carbon nanotubes provide flexibility and structural support in regions where the cathode material would otherwise be brittle, while the cathode material itself maintains its electrochemical activity. This local differentiation of functions (structural vs. electrochemical) resolves the flexibility-strength contradiction.
2Quantity of substance
If the electrode area is increased to increase battery capacity, then the battery capacity increases, but the battery volume increases, making it less suitable for small-sized applications
Solution Approach 1:
The patent transitions from a two-dimensional planar electrode structure to a three-dimensional wound structure. By winding multiple layers of thin electrodes around a central axis, the electrode area is dramatically increased without proportionally increasing the battery volume. This dimensional transformation allows high capacity to be achieved in a compact, coin-type form factor suitable for small-sized IoT sensors and other portable applications.
Solution Approach 2:
The patent employs a nested, wound structure where multiple electrode layers are wound around a central current collector axis, similar to a nested doll configuration. This allows the electrode area to be packed efficiently within a small volume, with each layer contributing to the total capacity while maintaining a compact overall geometry. The wound structure enables high capacity density in a small form factor.
3Quantity of substance
If a wound structure is used to increase electrode area and capacity, then the battery capacity increases, but the brittleness of the binder-free cathode makes it difficult to handle and wind as a co-continuous body
Solution Approach 1:
The carbon nanotube-binder-free cathode composite provides inherent flexibility and mechanical robustness that enables the cathode to be handled, wound, and processed as a co-continuous body. The carbon nanotube network acts as a flexible scaffold that prevents the brittle cathode material from fracturing during handling and winding operations, thus enabling the wound structure configuration while maintaining ease of operation.
Solution Approach 2:
The carbon nanotube network serves as an intermediary between the brittle cathode material particles and the flexible wound structure. It mediates the mechanical stresses during handling and winding, distributing forces throughout the cathode body and preventing localized fracture. This intermediary structure enables the cathode to be processed in a wound configuration despite the inherent brittleness of the binder-free cathode material.
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 solution enables a high-capacity metal-air battery with a binder-free cathode that is flexible and environmentally friendly, allowing for efficient discharge and reduced environmental impact through the use of abundant materials and biodegradable components.
Implementation Method 1
a separator that absorbs a liquid, which is to be an electrolytic solution
Implementation Method 2
oxygen in air used as the cathode active material is supplied from outside the battery
Implementation Method 3
In the air battery, oxygen in air used as the cathode active material is supplied from outside the battery
Implementation Method 4
For the anode, metals such as magnesium, iron, aluminum, and zinc can be used
Data Source
AI summary
A metal-air battery includes: a cathode formed of a co-continuous body having a three dimensional network structure formed by an integrated plurality of nanostructures having branches; a foil- or plate-like anode formed of a metal; a separator that absorbs a liquid, which is to be an electrolytic solution; and a foil- or plate-like current collector formed of a metal. The metal-air battery is formed with a wound structure in which the current collector, the cathode, the separator, the anode, and the separator are superimposed and wound in this order.