Alkaline Battery Separator Using Composite Fibers to Prevent Shrinkage
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Solution Overview
Problem
Alkaline battery separators face challenges with shrinkage in strong alkaline electrolytes, leading to reduced alkali resistance and increased risk of internal short circuits due to lack of stiffness, which affects battery performance and safety during handling.
Innovation Solution
An alkaline battery separator comprising alkali-resistant synthetic fibers, fibrillated organic solvent-spun cellulose fibers, and mercerized pulp in specific proportions, providing enhanced denseness, electrolyte retention, and stiffness strength to prevent shrinkage and internal short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a separator comprises alkali-resistance cellulose materials in a high compounding proportion to enhance electrolyte retention capability, then the electrolyte retention capability is improved, but the shrinkage by area becomes not less than 5% causing alkali resistance to decline
Solution Approach 1:
The separator uses a composite structure combining organic solvent-spun rayon fiber (providing electrolyte retention) with alkali-resistance synthetic fiber (providing dimensional stability). This composite material approach allows both high electrolyte retention capability and low shrinkage (not more than 3.5%) to be achieved simultaneously by leveraging the complementary properties of different materials.
2Quantity of substance
If the separator has high denseness and electrolyte retention capability, then the electrolyte retention is improved, but the stiffness strength is insufficient causing the sealing part to open on impact
Solution Approach 1:
The separator combines organic solvent-spun rayon fiber (providing electrolyte retention through its porous structure) with alkali-resistance synthetic fiber (providing mechanical strength and stiffness). This composite structure enables the separator to maintain both high electrolyte retention capability and sufficient stiffness strength to prevent opening on impact during handling.
3Reliability
If the separator comprises synthetic fiber to provide alkali resistance, then the alkali resistance is improved, but the electrolyte-absorbing property is reduced
Solution Approach 1:
The separator uses a composite of alkali-resistance synthetic fiber (providing chemical resistance to KOH electrolyte) and organic solvent-spun rayon fiber (providing hydrophilicity and electrolyte absorption). The synthetic fiber component ensures alkali resistance while the rayon fiber component maintains high electrolyte-absorbing property, resolving the trade-off between these two requirements.
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 separator maintains less than 3.5% shrinkage in a 40% KOH solution at 80°C, achieves high electrolyte retention, and exhibits drop impact resistance with a stiffness strength of at least 2 N, ensuring improved battery performance and safety.
Implementation Method 1
a fibrillated organic solvent-spun cellulose fiber
Implementation Method 2
a mercerized pulp
Implementation Method 3
retaining high electrolyte-absorbing property to generate sufficient electrogenic reactions
Data Source
AI summary
An alkaline battery separator including 25 to 62% by mass of an alkali-resistance synthetic fiber, 5 to 25% by mass of a fibrillated organic solvent-spun cellulose fiber having a Canadian standard freeness value of 10 to 280 ml, and 33 to 50% by mass of a mercerized pulp having a Canadian standard freeness value of not less than 550 ml, wherein the fibrillated organic solvent-spun cellulose fiber intertwines with the mercerized pulp.