Microporous Lead-Acid Battery Separators for Low Resistance
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Solution Overview
Problem
Lead acid batteries suffer from substantial conductivity loss over time, leading to reduced performance and lifespan, particularly due to increased internal electrical resistance and acid stratification.
Innovation Solution
Development of a microporous separator with decreased tortuosity, increased porosity, and improved wettability, featuring a shish-kebab morphology and high silanol group silica, which reduces electrical resistance and enhances acid diffusion, thereby maintaining high conductance and cold cranking amps over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional separators are used in lead acid batteries, then the battery can operate normally, but substantial conductivity loss occurs over time due to increased internal electrical resistance
Solution Approach 1:
The separator employs a microporous structure with optimized pore size distribution and porosity (30-60%) to enhance ion transport. The porous silica filler (40-60 wt%) creates additional pathways for ion diffusion, reducing electrical resistance and maintaining conductivity over time by facilitating efficient ion movement through the separator matrix.
Solution Approach 2:
The separator is constructed as a composite material combining polyolefin base polymer with dispersed silica filler particles (0.5-5 μm). This composite structure leverages the hydrophobic properties of polyolefin for chemical stability while the hydrophilic silica surfaces enhance wettability and ion transport, creating synergistic effects that reduce electrical resistance and improve long-term conductivity maintenance.
2Reliability
If separator porosity is increased to improve ion transport, then electrical resistance decreases, but mechanical strength may be compromised
Solution Approach 1:
The separator exhibits local quality variations through its composite structure, where the polyolefin matrix provides mechanical strength in regions requiring structural integrity, while the silica-filled porous regions provide enhanced ion transport pathways. This spatial differentiation of properties allows the separator to simultaneously achieve low electrical resistance and adequate mechanical strength.
Solution Approach 2:
The composite of polyolefin and silica creates a material where each component contributes its superior properties: polyolefin provides tensile strength and chemical resistance, while silica enhances porosity and wettability. The synergistic interaction in this composite system enables the separator to maintain mechanical integrity even with increased porosity (30-60%), as the silica framework supports the polymer matrix.
3Reliability
If silica filler content is increased to enhance wettability and ion transport, then electrical resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes the silica filler content within a specific range (40-60 wt%) to achieve the desired balance between wettability enhancement and manufacturing feasibility. This parameter optimization ensures sufficient hydrophilic surface area for improved acid diffusion while maintaining a composition that can be processed using conventional separator manufacturing techniques, avoiding excessive complexity.
Solution Approach 2:
The use of porous silica filler with controlled particle size (0.5-5 μm) and surface area (150-300 m²/g) creates an optimized pore network structure that enhances ion transport without requiring complex manufacturing processes. The porous structure of the filler itself contributes to the separator's overall porosity and ion conductivity, achieving high acid diffusion capability through material selection rather than process complexity.
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 improved separator significantly reduces electrical resistance by up to 30% and maintains high conductance and cold cranking amps, extending the battery's performance and lifespan while preventing acid stratification.
Implementation Method 1
a microporous separator with decreased tortuosity, increased porosity, and improved wettability, featuring a shish-kebab morphology and high silanol group silica, which reduces electrical resistance and enhances acid diffusion
Implementation Method 2
which reduces electrical resistance and enhances acid diffusion, thereby maintaining high conductance and cold cranking amps over time
Implementation Method 3
featuring a shish-kebab morphology and high silanol group silica
Data Source
AI summary
In accordance with at least selected embodiments, the present disclosure or invention is directed to improved battery separators, high conductance separators, improved lead-acid batteries, such as flooded lead-acid batteries, high conductance batteries, improved systems, and/or, improved vehicles including such batteries, and/or methods of manufacture or use of such separators or batteries, and/or combinations thereof. In accordance with at least certain embodiments, the present disclosure or invention is directed to improved lead acid batteries incorporating the improved separators and which exhibit increased conductance. Particular, non-limiting examples may include lead acid battery separators having structure or features designed to improve conductance, lower ER, lower water loss, and the like.