Lead-Acid Battery Separator Fiber Balance for Absorption and Assembly
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Solution Overview
Problem
Conventional separators for valve-regulated lead acid batteries face issues with dimensional mismatch during assembly, poor liquid absorption ratio, and compromised battery capacity and life due to inadequate consideration of the aspect ratio, tensile strength, and elongation percentage of glass fibers.
Innovation Solution
Optimizing the aspect ratio (average fiber length/average fiber diameter) of glass fibers in the separator to 130 to 205, with tensile strength of 0.20 N/mm² or more and elongation percentage between 2.0% and 9.0%, ensuring dimensional stability and improved liquid absorbability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the average fiber length of glass fiber is increased to improve liquid absorption ratio, then the liquid absorption ratio is improved, but the aspect ratio becomes too large causing excessive elongation and dimensional instability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aspect ratio of glass fibers within the range of 80 to 150, and the average fiber length within 0.5 to 2.0 mm. This optimization balances the liquid absorption capability with dimensional stability, preventing excessive elongation while maintaining adequate electrolyte absorption for battery operation.
2Strength
If the tensile strength of separator is increased to improve battery life, then the strength is improved, but the elongation percentage decreases causing poor assembly performance
Solution Approach 1:
The patent optimizes the tensile strength to be within 0.05 to 0.50 N/mm² and elongation percentage within 5 to 50%. This parameter optimization ensures the separator has sufficient strength for battery life while maintaining adequate elongation for easy assembly without cracking or deformation during installation.
3Quantity of substance
If the density of separator is decreased to improve liquid absorption ratio, then the liquid absorption ratio is improved, but the tensile strength decreases causing poor battery life
Solution Approach 1:
The patent balances density optimization with simultaneous control of tensile strength (0.05 to 0.50 N/mm²) and liquid absorption ratio (40 to 150%). This coordinated parameter optimization ensures adequate strength for battery life while maintaining sufficient liquid absorption capability, avoiding the trade-off between these properties.
4Strength
If organic fiber is added to glass fiber to increase sheet strength, then the tensile strength is improved, but the liquid absorption ratio decreases due to poor hydrophilicity
Solution Approach 1:
The patent extracts the problematic organic fiber component from the separator composition and uses glass fiber alone (100% glass fiber content). This eliminates the hydrophobicity issue caused by organic fibers while maintaining adequate tensile strength through optimized glass fiber aspect ratio and length parameters, thereby preserving liquid absorption ratio.
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 optimized separator maintains optimal physical properties, enhances battery capacity and life, and prevents defects during assembly by balancing fiber dimensions and strength, thus improving battery performance.
Implementation Method 1
how to swell the separator itself by allowing it to absorb a large amount of the electrolyte
Implementation Method 2
the ease of movement of the electrolyte at the interface between the electrode plate and the separator is the key point for improving the battery life
Data Source
AI summary
[Problem] To provide an optimum separator that simultaneously has basic physical properties essential for the characteristics of a separator for valve-regulated lead acid batteries and liquid absorbability while taking into account the improvement of the battery capacity and battery life and the good battery assembly performance.[Solution] The aspect ratio (average fiber length/average fiber diameter) of a glass fiber in a separator is 130 to 205, the tensile strength of the separator is 0.20 N/mm2 or more, and the elongation percentage at break of the separator is 2.0% or more and less than 9.0%.