Multilayer Non-Woven Mat for Lead-Acid Battery Electrodes
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Solution Overview
Problem
Conventional non-woven mats for lead-acid batteries face challenges in balancing wickability and tensile strength, leading to issues such as bleed-through and reduced battery performance due to high porosity and air permeability, which compromise the structural integrity and longevity of electrodes.
Innovation Solution
A multilayer non-woven mat design featuring a combination of coarse fibers and microfibers, with specific weight ratios and layer configurations to enhance wickability while maintaining tensile strength, is used to reinforce electrodes, incorporating a binder to bond the fibers and layers simultaneously, thereby reducing bleed-through and improving battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If non-woven mats use microfibers to improve wickability, then electrolyte absorption and distribution is enhanced, but tensile strength and structural integrity are reduced
Solution Approach 1:
The patent employs a composite non-woven mat structure combining microfibers (for wickability) with coarse fibers and binder materials (for tensile strength). This composite approach allows the mat to simultaneously achieve excellent electrolyte wicking properties through the microfiber network while maintaining structural integrity through the reinforcing coarse fiber framework and binder matrix, directly resolving the contradiction between wickability and tensile strength
Solution Approach 2:
The patent creates regions with different fiber compositions and properties within the non-woven mat. The microfiber-rich regions provide enhanced wickability for electrolyte distribution, while coarse fiber-reinforced regions provide structural support and tensile strength. This local differentiation of material properties allows the mat to perform both functions optimally in different zones, resolving the inherent trade-off between wickability and strength
2Difficulty of detecting and measuring
If non-woven mats increase porosity to enhance wickability, then electrolyte flow is improved, but tensile strength and electrode reinforcement are compromised
Solution Approach 1:
The patent uses a composite material system where high-porosity microfiber regions enable excellent wickability and electrolyte flow, while embedded coarse fibers and binder materials provide the necessary mechanical reinforcement. This composite structure allows the mat to maintain high porosity for wickability without sacrificing electrode reinforcement reliability, as the coarse fiber framework provides structural support even in the porous regions
Solution Approach 2:
The patent implements local quality differentiation by creating porous microfiber zones for optimal wickability and electrolyte penetration, while incorporating reinforced zones with higher coarse fiber content for structural support. This spatial variation in material composition allows different regions to specialize in either wickability or reinforcement, resolving the contradiction between porosity-enhanced wickability and overall structural reliability
3Strength
If non-woven mats use coarse fibers to improve tensile strength, then structural integrity is enhanced, but wickability and electrolyte absorption are reduced
Solution Approach 1:
The patent combines coarse fibers (providing tensile strength) with microfibers (providing wickability) in a composite non-woven mat structure. The coarse fibers form a load-bearing framework that ensures structural integrity and electrode reinforcement, while the microfiber network embedded within this framework provides the capillary channels necessary for excellent wickability and electrolyte absorption, thus resolving the contradiction between strength and wickability
Solution Approach 2:
The patent creates local quality variations by concentrating coarse fibers in regions requiring structural support and tensile strength, while maintaining microfiber dominance in regions optimized for electrolyte wicking and absorption. This spatial differentiation allows the mat to exhibit high tensile strength where needed while preserving excellent wickability in the microfiber-rich zones, resolving the trade-off between these two properties
4Reliability
If non-woven mats reduce air permeability to limit bleed-through, then active material retention is improved, but wickability and electrolyte distribution are hindered
Solution Approach 1:
The patent employs a composite structure where microfibers create a dense network that reduces air permeability and limits active material bleed-through, while simultaneously maintaining adequate porosity and interconnected channels for electrolyte wicking and distribution. The coarse fibers and binder materials provide structural support that maintains this balanced pore structure, preventing collapse that would otherwise occur in purely microfiber mats, thus resolving the contradiction between active material retention and wickability
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 multilayer mat effectively limits bleed-through and enhances the structural support and wickability of electrodes, extending battery life and performance by optimizing fiber composition and layer structure.
Implementation Method 1
Non-woven mats having the advantage of wicking electrolyte along the electrode plates to benefit battery performance
Implementation Method 2
A binder is configured to simultaneously bind the coarse fibers in the first layer together, the microfibers in the second layer together, and at least some of the coarse fibers in the first layer to at least some of the microfibers in the second layer together
Data Source
AI summary
A multilayer non-woven mat for a lead-acid battery includes a first layer of non-woven web of fibers including coarse fibers having an average fiber diameter from about 6 μm to about 25 μm and a second layer of non-woven web of fibers including microfibers having an average diameter from about 0.5 μm to about 5 μm. The multilayer non-woven mat includes a binder configured to simultaneously bind the coarse fibers in the first layer together, the microfibers in the second layer together, and at least some of the coarse fibers in the first layer to at least some of the microfibers in the second layer together. The first layer is configured to absorb an active material of an electrode of the lead acid battery, and the second layer is configured to block the active material of the electrode from passing through the non-woven glass mat.