Self-Supporting Negative Electrode for Rechargeable Button Cells
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Solution Overview
Problem
Conventional zinc-air button cells used in hearing aids have high power consumption and are non-rechargeable, leading to frequent replacements and environmental concerns due to mercury content, while rechargeable nickel metal hydride batteries offer low capacity and require frequent recharging.
Innovation Solution
A button cell design featuring a self-supporting negative electrode with a hydrogen storage alloy and a conductive polymer, eliminating the need for a nickel basket, and an alkaline electrolyte in a thin, stable housing with a unique seal configuration, enhancing capacity and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If zinc-air batteries are used to achieve high capacity, then the battery capacity is improved, but the battery becomes non-rechargeable and requires frequent replacement
Solution Approach 1:
The patent changes the chemical composition parameters of the electrodes, using hydrogen storage alloy for the negative electrode and nickel oxyhydroxide for the positive electrode, enabling the battery to be rechargeable while maintaining high capacity through optimized material properties and ratios
2Adaptability or versatility
If nickel metal hydride batteries are used to achieve rechargeability, then the battery becomes rechargeable, but the capacity becomes very low requiring frequent recharging
Solution Approach 1:
The patent uses composite materials including hydrogen storage alloy particles combined with conductive polymers and binders in the negative electrode, and nickel oxyhydroxide with conductive additives in the positive electrode, creating a composite structure that achieves both high capacity and rechargeability
3Device complexity
If conventional electrodes are used in button cells, then the structure is simple, but the electrodes lack structural integrity and disintegrate during operation
Solution Approach 1:
The patent employs composite materials where conductive polymers and binders form a matrix that holds the active material particles together, creating electrodes with sufficient mechanical strength and structural integrity to prevent disintegration during operation while maintaining electrical conductivity
4Quantity of substance
If zinc-air batteries are used to achieve high capacity, then the battery capacity is improved, but environmental harm increases due to mercury content
Solution Approach 1:
The patent changes the chemical composition by eliminating mercury-containing materials and using environmentally friendly alternatives such as hydrogen storage alloy and nickel oxyhydroxide, maintaining high capacity while removing harmful substances from the battery system
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 button cell achieves higher capacity and excellent cycle stability, reducing the need for frequent replacements and minimizing environmental impact by using a self-supporting structure and optimized electrode composition.
Implementation Method 1
The negative electrode has a hydrogen storage alloy as the active material
Implementation Method 2
an alkaline electrolyte in a thin, stable housing
Data Source
Figure 1
AI summary
The invention describes a galvanic element with a positive electrode, a negative electrode and a separator, which are arranged in a housing comprising a cell cup and a cell cover, which are insulated from one another by means of a seal. The galvanic element is particularly characterized by the fact that it has a negative electrode, which is present in the form of a preferably tablet-shaped moulding with a self-supporting structure and/or that it has a seal, which extends bearing against the inner wall of the cell cup towards the base of the cell cup. The invention also describes a moulding which is suitable for use as a negative electrode in such a galvanic element, comprising a hydrogen storage alloy and possibly at least one hydrophobic water-insoluble polymer and/or at least one conductant. The moulding is characterized by the fact that it has a density of between 5.0 g/cm3 and 7.5 g/cm3.