Metal-Air Button Cell Conductive Coating for Impedance Control
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Solution Overview
Problem
Metal-air button cells exhibit high variance in electrochemical properties, resulting in unexpectedly high impedance values due to inadequate electrical contact between conductor structures and housing terminals.
Innovation Solution
A closed cell housing with a disc-shaped air cathode covering entry/exit openings, featuring an electrically conductive coating on the inner side wall with a high fraction of conductive particles, improves electrical contact and secures the air cathode in place, reducing impedance variance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the air cathode is positioned flat on the housing base to cover the openings, then oxygen can contact the air cathode immediately, but electrical contact between conductor structures and housing terminals is inadequate, resulting in high impedance values
Solution Approach 1:
The patent introduces an electrically conductive coating as an intermediary substance between the air cathode periphery and the housing inner side wall. This coating layer mediates the electrical contact, allowing electrons to be effectively evacuated from the air cathode to the housing terminal, thereby resolving the inadequate electrical contact issue while maintaining the direct oxygen contact configuration.
2Quantity of substance
If holes are stamped into the housing as entry and exit openings, then oxygen can be supplied to the cathode, but the electrical contact between the air cathode and housing terminal remains insufficient
Solution Approach 1:
The patent applies electrically conductive coating specifically at the localized region where the air cathode periphery contacts the housing inner side wall. This local application of conductive material针对性地 addresses the electrical contact issue at the critical interface without affecting other parts of the housing or requiring changes to the opening configuration.
3Manufacturing precision
If a porous filter paper air distributor is provided between the air cathode and housing base, then oxygen distribution may be improved, but the electrical contact issue persists
Solution Approach 1:
The electrically conductive coating serves as an intermediary that bridges the electrical gap between the air cathode and housing terminal. Unlike the porous filter paper which addresses oxygen distribution, the conductive coating specifically targets the electrical contact problem by providing a conductive pathway at the periphery contact zone.
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 electrically conductive coating significantly reduces impedance variations by enhancing electrical conductivity and providing a secure adhesive connection between the air cathode and the housing, leading to improved electrochemical performance.
Implementation Method 1
an electrically conductive coating is arranged on the inner side of the side wall at a height on which the periphery bears, and the electrically conductive coating has a matrix of a binding agent and, embedded therein, electrically conductive particles
Implementation Method 2
Gas-diffusion electrodes are electrodes in which the materials involved in the electrochemical reaction (typically a catalyst, an electrolyte and atmospheric oxygen) are present alongside one another in a solid, liquid and gaseous state and can come into contact with one another. When discharging, the catalyst catalyses the reduction of atmospheric oxygen
Implementation Method 3
a metal-based anode and an air cathode separated from one another by an ion-conductive electrolyte. When discharging, oxygen is reduced on the air cathode while taking up electrons. Hydroxide ions which can migrate via the electrolyte to the anode are produced
Data Source
AI summary
Metal-air button cells including a closed cell housing and, arranged therein, an air cathode and a metal-based anode separated from one another by a separator, wherein the cell housing is substantially composed of a first housing half-part and a second housing half-part; the housing half-parts are configured to be cup-shaped and have a base and a circumferential side wall; the base of the second housing half-part has one or more entry and/or exit openings for atmospheric oxygen; and the air cathode is configured to be disc-shaped and is positioned on the base of the second housing half-part such that it covers the entry and/or exit openings and its periphery bears on the inner side of the circumferential side wall of the second housing half-part.