Lead-Acid Battery Pasting Paper With Tuned Wettability and Pore Size
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Solution Overview
Problem
Conventional pasting papers for lead acid batteries face issues such as material dissolution in sulfuric acid, poor wettability, increased internal resistance, and electrolyte stratification, leading to reduced battery life and performance.
Innovation Solution
A nonwoven pasting paper composed of a blend of glass fibers, acid-resistant organic fibers, and non-acid-resistant organic fibers, with specific weight ratios and fiber diameters, enhancing wettability, tensile strength, and pore size to prevent active material fall-off and electrolyte stratification while maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a paper (pulp 100%) is used as pasting paper, then it dissolves in sulfuric acid and disappears, but this causes active material fall-off and reduces battery life
Solution Approach 1:
The patent uses a composite material consisting of glass fiber (40-60 wt%) and polyester fiber (40-60 wt%) to create a pasting paper that combines the acid resistance of glass fiber with the binding properties of polyester fiber. This composite structure prevents both dissolution and active material fall-off, resolving the contradiction between battery life and active material retention.
2Reliability
If a glass fiber nonwoven fabric is used to prevent active material fall-off, then the fabric becomes dense and thick, but this increases internal resistance and reduces battery capacity
Solution Approach 1:
The patent applies local quality by using a blend of glass fiber and polyester fiber with different properties in specific proportions. The glass fiber provides local acid resistance and structural integrity, while the polyester fiber provides local binding and flexibility. This localized functional distribution maintains active material retention while preventing excessive density that would increase internal resistance.
3Strength
If the glass fiber surface is coated with hydrophobic resin to maintain strength, then the fiber strength is maintained, but the wettability decreases and electrolyte affinity is impaired
Solution Approach 1:
The patent introduces polyester fiber as an intermediary material that naturally possesses both strength and good wettability with electrolyte. This intermediary fiber compensates for the hydrophobicity of glass fiber without requiring chemical modification, thereby maintaining both fiber strength and electrolyte affinity through the synergistic effect of the fiber blend.
4Reliability
If a dense glass fiber nonwoven fabric is used instead of thin paper, then basic lead sulfate permeation is prevented, but the battery capacity decreases and internal resistance deteriorates
Solution Approach 1:
The patent changes the key parameter of fiber composition from 100% glass fiber to a blend of glass fiber (40-60 wt%) and polyester fiber (40-60 wt%). This parameter change modifies the overall density and pore structure of the nonwoven fabric, achieving adequate permeation resistance while maintaining sufficient porosity to prevent excessive internal resistance and preserve battery capacity.
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 active material fall-off and electrolyte stratification, reduces internal resistance, and improves battery life by allowing gradual pore size increase and elution of non-acid-resistant fibers, maintaining adhesion and electrolyte retention.
Implementation Method 1
the wettability of the nonwoven fabric is 20 sec/mL or less, and the maximum pore size is 70 μm or less
Implementation Method 2
a non-acid-resistant organic fiber...allowing gradual pore size increase and elution of non-acid-resistant fibers
Data Source
AI summary
[Problem] To provide a pasting paper that is composed of a nonwoven fabric using at least three types of fibers as constituent materials, and that, in a lead acid battery, has a function to prevent fall-off of an active material in assembling a battery, prevents electrolyte stratification occurring accompanying charging and discharging of the lead acid battery, and moreover inhibits a decrease in the charge acceptability of the lead acid battery by reducing the internal resistance value of the lead acid battery while maintaining prevention of fall-off of the active material and prevention of electrolyte stratification against a decrease in battery performance caused by a change in the size of the active material with repeated battery cycles.[Means for Resolution] A pasting paper for lead acid batteries composed of a nonwoven fabric constituted by at least a glass fiber, an acid-resistant organic fiber, and a non-acid-resistant organic fiber, characterized in that the nonwoven fabric has a wettability of 20 sec/mL or less and a maximum pore size of 70 μm or less.