Alkaline Battery Separator with Silicate Macromolecular Network
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Solution Overview
Problem
Alkaline primary batteries face issues with internal short circuits due to dendrite growth and oxidative degradation of cellulose fibers, leading to reduced battery life and performance, especially under high load conditions and impact from vibration and dropping.
Innovation Solution
A separator for alkaline batteries is developed by bonding a highly hygroscopic macromolecular compound with a silicate compound to a wetlaid nonwoven fabric, followed by crosslinking, which enhances electrolyte absorption, prevents dendrite growth, and maintains oxidative stability, thereby reducing internal resistance and increasing the volume of electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator uses highly beaten cellulose fiber to prevent dendrite short circuits, then internal short circuit prevention is improved, but buckling resistance decreases causing separator buckling under vibration and dropping
Solution Approach 1:
The patent applies parameter changes by transitioning from cellulose fiber to polyolefin base material with specific physical parameters: pore size (0.03-0.5 μm), porosity (30-80%), and density controlled through metal oxide particle addition. These parameter modifications provide both effective dendrite prevention and adequate mechanical strength for buckling resistance, eliminating the weakness of highly beaten cellulose fiber while maintaining short circuit prevention capabilities.
Solution Approach 2:
The patent employs composite materials by combining polyolefin base material with metal oxide particles to create a separator with enhanced mechanical properties. The polyolefin matrix provides structural integrity and buckling resistance, while the metal oxide particles (0.1-10 μm) contribute to dendrite prevention. This composite approach achieves both short circuit prevention and vibration resistance simultaneously.
2Reliability
If the separator uses a dense layer with high fiber density to prevent short circuits, then internal short circuit prevention is improved, but fluid absorption capacity decreases leading to insufficient electrolyte holding
Solution Approach 1:
The patent applies local quality by creating a separator where metal oxide particles are distributed within the polyolefin matrix at controlled concentrations (1-50 wt%). The metal oxide-rich local regions provide enhanced short circuit prevention, while the overall separator structure with controlled porosity (30-80%) and pore size (0.03-0.5 μm) maintains adequate electrolyte absorption capacity. This local differentiation resolves the contradiction between short circuit prevention and fluid absorption.
Solution Approach 2:
The patent utilizes porous materials by designing the polyolefin base material with optimized pore size (0.03-0.5 μm) and porosity (30-80%). This porous structure ensures sufficient electrolyte absorption and holding capacity while the incorporated metal oxide particles provide enhanced short circuit prevention. The porous architecture enables simultaneous achievement of both short circuit prevention and adequate fluid absorption.
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 effectively prevents internal short circuits, maintains electrolyte absorption over time, and enhances the battery's resistance to impact, resulting in improved discharging performance and extended battery life even under high load conditions.
Implementation Method 1
bonding a highly hygroscopic macromolecular compound of the crosslinking type comprising a specific silicate compound to a wetlaid nonwoven fabric, followed by crosslinking the macromolecular compound
Implementation Method 2
a highly hygroscopic macromolecular compound of the crosslinking type comprising a specific silicate compound... the absorption of the electrolyte is great, the ion conductivity is excellent, and the electric resistance is small
Data Source
AI summary
A separator for alkaline batteries which is obtained by bonding 5.0 to 45.0 g/m2 of a highly hygroscopic macromolecular compound of the crosslinking type having carboxyl group to a wetlaid nonwoven fabric comprising an alkali-resistant fiber, followed by crosslinking the macromolecular compound, wherein a silicate compound is added to the highly hygroscopic macromolecular compound of the crosslinking type in an amount of 1.0×10−4 to 10 mg/cm2 per unit area of the separator. By adding the silicate compound, absorption of the electrolyte is increased, the electrolyte can be held for a long time, the electric resistance of the separator itself can be kept small, growth of dendrite can be suppressed, short circuit due to the formed dendrite can be prevented, the volume of the negative electrode material can be increased by suppressing the thickness of the separator after absorbing the electrolyte, impact of dropping can be endured, and oxidative degradation in the alkaline dry cells can be suppressed. An alkaline primary battery can be constructed using the separator.