Rubber-Impregnated Lead-Acid Separator for Oxidation Resistance
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Solution Overview
Problem
Lead/acid battery separators are prone to oxidation due to contaminants like chromium, manganese, and copper, leading to reduced cycle life and battery failure, especially when used with contaminated water and acid.
Innovation Solution
A microporous membrane battery separator incorporating up to 12% rubber, such as rubber latex or tire crumb, which is impregnated into the membrane, providing resistance to oxidation from these contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyolefin separators are used, then manufacturing cost and ease of manufacture are maintained, but the separator is prone to oxidation from contaminants leading to reduced cycle life
Solution Approach 1:
The patent applies composite materials by combining rubber (natural or synthetic) with polyolefin to create a separator that resists oxidation from contaminants. The rubber component (0.1-10% by weight) forms a protective network within the polyolefin matrix, creating a composite structure that maintains the base material's manufacturing advantages while adding oxidation resistance through the rubber's chemical properties.
Solution Approach 2:
The patent changes the chemical composition parameters of the separator by introducing rubber content at specific concentrations (0.1-10% by weight). This parameter change transforms the separator from oxidation-prone polyolefin to oxidation-resistant composite, while maintaining manufacturing feasibility through established rubber incorporation techniques.
2Reliability
If rubber is added to the separator to prevent oxidation, then oxidation resistance improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent optimizes the rubber content parameter to 0.1-10% by weight, which is sufficient to provide oxidation resistance while remaining compatible with existing manufacturing processes. This parameter range ensures the rubber disperses adequately in the polyolefin matrix without requiring fundamentally new manufacturing equipment or techniques.
Solution Approach 2:
The patent maintains the microporous structure of the separator while incorporating rubber, allowing the porous network to facilitate rubber distribution throughout the matrix. The porous architecture enables simple incorporation methods such as mixing rubber particles into the molten polyolefin during extrusion, avoiding complex multi-step manufacturing processes.
3Reliability
If higher rubber content is used, then oxidation resistance improves, but the separator's mechanical properties and porosity may deteriorate
Solution Approach 1:
The patent identifies and optimizes the critical parameter of rubber content, setting the upper limit at 10% by weight. Below this threshold, the rubber provides sufficient oxidation resistance through its chemical structure, while the polyolefin matrix maintains adequate mechanical strength and porosity for battery operation. Exceeding this ratio would compromise the continuous polyolefin phase necessary for structural integrity.
Solution Approach 2:
The patent leverages the microporous structure to accommodate rubber particles without collapsing the pore network. The porous architecture provides space for rubber dispersion while maintaining ion transport pathways, ensuring that mechanical integrity and electrochemical function are preserved even with rubber addition.
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 rubber-impregnated microporous membrane significantly increases the cycle life of lead/acid batteries by preventing oxidation, as demonstrated by improved elongation resistance compared to conventional separators when exposed to contaminants like chromium.
Implementation Method 1
A battery separator for a lead/acid battery is resistant to oxidation arising from the use of water or acid containing contaminants
Data Source
AI summary
A battery separator for a lead/acid battery is resistant to oxidation arising from the use of water or acid containing contaminants, for example chromium (Cr), manganese (Mn), titanium (Ti), copper (Cu), and the like. The separator is a microporous membrane including a rubber. The rubber is no more than about 12% by weight of the separator. The rubber may be rubber latex, tire crumb, and combinations thereof. The rubber may be impregnated into the microporous membrane. The microporous membrane may be a microporous sheet of polyolefin, polyvinyl chloride, phenol-formaldehyde resins, cross-linked rubber, or nonwoven fibers. A method for preventing the oxidation and/or extending battery life of the separator is also included.