Alkaline Cell Separator Pore Structure for Lower Wrap Volume
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Solution Overview
Problem
Conventional alkaline electrochemical cells have thick separators that occupy significant volume, reducing the space available for active ingredients and leading to decreased performance, especially in smaller cells.
Innovation Solution
A non-conductive, porous separator material with a mean pore size of about 1 micron to 6 microns and air permeability of 0.5 cc/cm2/s to 3.8 cc/cm2/s at 125 Pa is used, allowing for a reduced number of separator wraps and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-woven separator sheet is wound multiple times to ensure sufficient separation between electrodes, then reliability of preventing leakage and shorting is improved, but volume of the separator increases, reducing the volume available for active ingredients
Solution Approach 1:
The patent changes the pore size parameter of the separator material to a specific range (0.5-5 microns mean pore size) to achieve both effective separation and reduced volume. This parameter optimization allows fewer wraps to be needed while maintaining separation effectiveness.
Solution Approach 2:
The patent uses a composite non-woven material structure combining specific fiber types and pore characteristics to achieve high separation efficiency in a thinner profile, reducing the number of wraps needed compared to conventional separators.
2Volume of moving object
If the separator thickness is reduced to increase active ingredient volume, then volume for active ingredients is improved, but separation effectiveness and prevention of shorting may worsen
Solution Approach 1:
The patent optimizes the pore size parameter (mean pore size of 0.5-5 microns) and air permeability to achieve effective separation in a thinner separator structure, maintaining shorting prevention while reducing overall separator volume.
Solution Approach 2:
The patent employs a porous non-woven material with specifically controlled pore characteristics that provide effective ion separation and shorting prevention in a reduced thickness, allowing thinner separator design without compromising reliability.
3Manufacturing precision
If the pore size of the separator is reduced to improve separation precision, then measurement precision of ion transport is improved, but air permeability decreases, reducing electrolyte flow
Solution Approach 1:
The patent optimizes the pore size parameter to a specific range (mean pore size 0.5-5 microns) that balances separation precision with adequate air permeability for electrolyte flow, achieving both precise ion separation and sufficient productivity.
Solution Approach 2:
The patent uses a composite non-woven material structure that maintains precise pore geometry for effective separation while preserving sufficient porosity and air permeability to ensure adequate electrolyte flow and cell productivity.
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 improved separator reduces the volume occupied by the separator, allowing for increased active ingredient capacity, enhanced mechanical strength, and improved electrolyte permeability, leading to better cell performance and reduced short-circuiting.
Implementation Method 1
the separator is permeable to hydroxide ions and water
Implementation Method 2
the separator is permeable to hydroxide ions and water
Implementation Method 3
an air permeability of about 0.5 cc/cm2/s to about 3.8 cc/cm2/s at 125 Pa
Data Source
AI summary
An alkaline electrochemical cell includes a cathode; a gelled anode having an anode active material and an electrolyte; and a separator disposed between the cathode and the anode; wherein the separator includes a non-conductive, porous material having a mean pore size of about 1 micron to about 5 microns, a maximum pore size of about 19 microns, and an air permeability of about 0.5 cc/cm2/s to about 3.8 cc/cm2/s at 125 Pa.