Composite Battery Separator with Cured Rubber Powder
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Solution Overview
Problem
Conventional rubber-containing separators for deep-cycle lead-acid batteries face challenges such as high resistance to ionic flow, high production costs, and limited supply, while attempts to improve them, like using pulverized rubber-based powders, suffer from inefficiencies and short supply issues, necessitating a low-cost, low-resistance separator that reduces water loss and extends cycle life.
Innovation Solution
A microporous silica-filled polyolefin separator incorporating cured rubber powder with low or no porosity, sourced from recycled tires, which increases hydrogen evolution overpotential and decreases antimony deposition on the negative electrode, enhancing electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional rubber-containing separators are used for deep-cycle batteries, then water loss is reduced and cycle life is extended, but resistance to ionic flow increases and production cost increases
Solution Approach 1:
The patent uses porous silica particles as the primary filler material in the separator matrix. The porous structure of silica provides channels for ionic flow while maintaining the physical separation between electrodes. This resolves the contradiction by allowing ionic transport through the porous silica network while the rubber particles provide the water loss reduction benefits without requiring high rubber content that would block pores.
Solution Approach 2:
The patent creates a composite separator consisting of polyethylene matrix, porous silica particles, and rubber particles. This composite structure combines the advantages of each material: polyethylene provides chemical resistance and structural integrity, porous silica provides ionic flow pathways and wettability, and rubber particles reduce water loss during charging. The composite approach allows achieving both low ionic resistance and extended cycle life simultaneously.
2Duration of action of stationary object
If conventional rubber-containing separators are used for deep-cycle batteries, then water loss is reduced and cycle life is extended, but production cost increases
Solution Approach 1:
The patent replaces expensive conventional rubber materials with cheaper alternatives: using pulverized rubber from recycled tires instead of virgin rubber, and using porous silica particles that can be produced cost-effectively. This substitution maintains the functional benefits of rubber-containing separators (water loss reduction) while significantly reducing material costs and making the separator more economically viable for mass production.
Solution Approach 2:
The patent utilizes pulverized rubber obtained from recycled tires, transforming waste material into a valuable component for separator manufacturing. This approach reduces raw material costs and aligns with sustainable manufacturing practices, thereby reducing production costs while maintaining the functional benefits of rubber in the separator structure.
3Loss of substance
If pulverized rubber-based powders are used to improve separator performance, then water loss reduction is achieved, but supply is limited and production efficiency decreases
Solution Approach 1:
The patent uses porous silica particles that serve multiple functions simultaneously: providing wettability for the acid electrolyte, defining the pore structure for ionic flow, and acting as a filler that reduces water loss. This multi-functionality eliminates the need for separate rubber powder additions and simplifies the manufacturing process, thereby improving production efficiency while maintaining water loss reduction benefits.
Solution Approach 2:
The patent changes the physical and chemical parameters of the separator by incorporating porous silica with specific surface area and pore size characteristics. The high surface area of porous silica enhances electrolyte wettability and ionic conductivity, while the controlled pore structure regulates water transport. This parameter optimization achieves water loss reduction through a unified material system that is more readily available and easier to manufacture than conventional rubber-based solutions.
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 results in improved electrochemical performance, reduced water loss, and extended cycle life for deep-cycle lead-acid batteries by increasing the active ingredient's quantity and slowing its diffusion, thereby maintaining performance over long application times.
Implementation Method 1
incorporating cured rubber powder with low or no porosity, sourced from recycled tires, which increases hydrogen evolution overpotential and decreases antimony deposition on the negative electrode
Implementation Method 2
incorporating cured rubber powder with low or no porosity, sourced from recycled tires, which increases hydrogen evolution overpotential and decreases antimony deposition on the negative electrode
Implementation Method 3
provides space for an electrolyte to reside. Such separators are formed of materials that are resistant to the sulfuric acid electrolyte and sufficiently porous to permit the electrolyte to reside in the pores of the separator material, thereby permitting ionic current flow with low resistance between adjacent positive and negative plates
Implementation Method 4
sufficiently porous to permit the electrolyte to reside in the pores of the separator material
Data Source
AI summary
A microporous silica-filled polyolefin separator (80) has a material composition that includes a fraction of cured rubber powder exhibiting low or no porosity. The cured rubber powder is a material derived from one or both of passenger and truck tires. The cured rubber powders exhibit the properties of increasing hydrogen evolution overpotential on the negative lead electrode and of decreasing the effect of antimony deposited on the negative electrode of the lead-acid battery. Incorporation of these cured rubber powders into the formulation of a microporous silica-filled polyethylene separator results in improved electrochemical properties in deep-cycle lead-acid batteries.